Understanding Cancer - Symptoms
Knowledge they say is power.but more powerful is the application of knowledge. Knowing about the following symptom that precede cancer development may help you.
What Are the Symptoms of Cancer?
In its early stages, cancer usually has no symptoms, but eventually a malignant tumor will grow large enough to be detected. As it continues to grow, it may press on nerves and produce pain, penetrate blood vessels and cause bleeding, or interfere with the function of a body organ or system.
The Seven Warning Signs of Cancer
To remember the seven early warning signs of cancer (as designated by the American Cancer Society), think of the word CAUTION:
C hange in bowel or bladder habits.
A sore that does not heal.
U nusual bleeding or discharge.
T hickening or lump in the breast, testicles, or elsewhere.
I ndigestion or difficulty swallowing.
O bvious change in the size, color, shape, or thickness of a wart, mole, or mouth sore.
N agging cough or hoarseness.
The following symptoms may also signal the presence of some form of cancer:
Persistent headaches
Unexplained loss of weight or appetite
Chronic pain in bones
Persistent fatigue, nausea, or vomiting
Persistent low-grade fever, either constant or intermittent
Repeated instances of infection
Call Your Doctor About Cancer If:
You develop symptoms that may signal cancer, are not clearly linked to another cause, and persist for more than two weeks. You should schedule a medical examination. If the cause of your symptoms is cancer, early diagnosis and treatment will offer a better chance of cure
source: webMD
Thursday, October 1, 2009
15 Cancer Symptoms Women Ignore
WebMD uncovers common cancer warning signs women often overlook.
By Kathleen DohenyWebMD Feature
Reviewed by Louise Chang, MD
WebMD uncovers common cancer warning signs women often overlook.
By Kathleen DohenyWebMD Feature
Reviewed by Louise Chang, MD
Women tend to be more vigilant than men about getting recommended health checkups and cancer screenings, according to studies and experts.
They're generally more willing, as well, to get potentially worrisome symptoms checked out, says Mary Daly, MD, oncologist and head of the department of clinical genetics at Fox Chase Cancer Center in Philadelphia.
But not always. Younger women, for instance, tend to ignore symptoms that could point to cancer. "They have this notion that cancer is a problem of older people," Daly tells WebMD. And they're often right, but plenty of young people get cancer, too.
Of course, some women are as skilled as men are at switching to denial mode. "There are people who deliberately ignore their cancer symptoms," says Hannah Linden, MD, a medical oncologist. She is a joint associate member of the Fred Hutchinson Cancer Research Center and associate professor of medicine at the University of Washington School of Medicine, Seattle. It's usually denial, but not always, she says. "For some, there is a cultural belief that cancer is incurable, so why go there."
Talking about worrisome symptoms shouldn't make people overreact, says Ranit Mishori, MD, an assistant professor of family medicine at the Georgetown University School of Medicine in Washington, D.C. "I don't want to give people the impression they should look for every little thing," she says.
With that healthy balance between denial and hypochondria in mind, WebMD asked experts to talk about the symptoms that may not immediately make a woman worry about cancer, but that should be checked out. Read on for 15 possible cancer symptoms women often ignore.
No. 1: Unexplained Weight Loss
Many women would be delighted to lose weight without trying. But unexplained weight loss -- say 10 pounds in a month without an increase in exercise or a decrease in food intake -- should be checked out, Mishori says.
"Unexplained weight loss is cancer unless proven not," she says. It could, of course, turn out to be another condition, such as an overactive thyroid.
Expect your doctor to run tests to check the thyroid and perhaps order a CT scan of different organs. The doctor needs to "rule out the possibilities, one by one," Mishori says.
No. 2: Bloating
Bloating is so common that many women just live with it. But it could point to ovarian cancer. Other symptoms of ovarian cancer include abdominal pain or pelvic pain, feeling full quickly -- even when you haven't eaten much -- and urinary problems, such as having an urgent need to go to the bathroom.
If the bloating occurs almost every day and persists for more than a few weeks, you should consult your physician. Expect your doctor to take a careful history and order a CT scan and blood tests, among others.
No. 3: Breast Changes
Most women know their breasts well, even if they don't do regular self-exams, and know to be on the lookout for lumps. But that's not the only breast symptom that could point to cancer. Redness and thickening of the skin on the breast, which could indicate a very rare but aggressive form of breast cancer, inflammatory breast cancer, also needs to be examined, Linden says. "If you have a rash that persists over weeks, you have to get it evaluated," she says.
Likewise, if the look of a nipple changes, or if you notice discharge (and aren’t breastfeeding), see your doctor. "If it's outgoing normally and turns in," she says, that's not a good sign. "If your nipples are inverted chronically, no big deal." It's the change in appearance that could be a worrisome symptom.
If you have breast changes, expect your doctor to take a careful history, examine the breast, and order tests such as mammogram, ultrasound,MRI, and perhaps a biopsy
No. 4: Between-Period Bleeding or Other Unusual Bleeding
''Premenopausal women tend to ignore between-period bleeding," Daly says. They also tend to ignore bleeding from the GI tract, mistakenly thinking it is from their period. But between-period bleeding, especially if you are typically regular, bears checking out, she says. So does bleeding after menopause, as it could be a symptom of endometrial cancer. GI bleeding could be a symptom of colorectal cancer.
Think about what's normal for you, says Debbie Saslow, PhD, director of breast and gynecologic cancer at the American Cancer Society in Atlanta. "If a woman never spots [between periods] and she spots, it's abnormal for her. For someone else, it might not be."
"Endometrial cancer is a common gynecologic cancer," Saslow says. "At least three-quarters who get it have some abnormal bleeding as an early sign."
Your doctor will take a careful history and, depending on the timing of the bleeding and other symptoms, probably order an ultrasound or biopsy.
''Premenopausal women tend to ignore between-period bleeding," Daly says. They also tend to ignore bleeding from the GI tract, mistakenly thinking it is from their period. But between-period bleeding, especially if you are typically regular, bears checking out, she says. So does bleeding after menopause, as it could be a symptom of endometrial cancer. GI bleeding could be a symptom of colorectal cancer.
Think about what's normal for you, says Debbie Saslow, PhD, director of breast and gynecologic cancer at the American Cancer Society in Atlanta. "If a woman never spots [between periods] and she spots, it's abnormal for her. For someone else, it might not be."
"Endometrial cancer is a common gynecologic cancer," Saslow says. "At least three-quarters who get it have some abnormal bleeding as an early sign."
Your doctor will take a careful history and, depending on the timing of the bleeding and other symptoms, probably order an ultrasound or biopsy.
No. 5: Skin Changes
Most of us know to look for any changes in moles -- a well-known sign of skin cancer. But we should also watch for changes in skin pigmentation, Daly says.
If you suddenly develop bleeding on your skin or excessive scaling, that should be checked, too, she says. It's difficult to say how long is too long to observe skin changes before you go to the doctor, but most experts say not longer than several weeks.
No. 6: Difficulty Swallowing
If you have difficulty swallowing, you may have already changed your diet so chewing isn't so difficult, perhaps turning to soups or liquid foods such as protein shakes.
But that difficulty could be a sign of a GI cancer, such as in the esophagus, says Leonard Lichtenfeld, MD, deputy chief medical officer at the American Cancer Society.
Expect your doctor to take a careful history and order tests such as a chest X-ray or exams of the GI tract. o. 7: Blood in the Wrong Place
If you notice blood in your urine or your stool, don’t assume it's from a hemorrhoid, says Mishori. "It could be colon cancer."
Expect your doctor to ask questions and perhaps order testing such as a colonoscopy, an exam of the colon to look for cancer.
Seeing blood in the toilet bowl may actually be from the vagina if a woman is menstruating, Mishori says. But if not, it should be checked to rule out bladder or kidney cancer, she says.
Coughing up blood should be evaluated, too. One occasion of blood in the wrong place may not point to anything, Mishori says, but if it happens more than once, go see your doctor.
No. 8: Gnawing Abdominal Pain and Depression
Any woman who's got a pain in the abdomen and is feeling depressed needs a checkup, says Lichtenfeld. Some researchers have found a link between depression and pancreatic cancer, but it's a poorly understood connection.
No. 9: Indigestion
Women who have been pregnant may remember the indigestion that occurred as they gained weight. But indigestion for no apparent reason may be a red flag.
It could be an early clue to cancer of the esophagus, stomach, or throat.
Expect your doctor to take a careful history and ask questions about the indigestion before deciding which tests to order, if any.
No. 10: Mouth Changes
Smokers should be especially alert for any white patches inside the mouth or white spots on the tongue, according to the American Cancer Society. Both can point to a precancerous condition called leukoplakia that can progress to oral cancer.
Ask your dentist or doctor to take a look and decide what should be done next.
No. 11: Pain
As people age they seem to complain more of various aches and pains, but pain, as vague as it may be, can also be an early symptom of some cancers, although most pain complaints are not from cancer.
Pain that persists and is unexplained needs to be checked out. Expect your physician to take a careful history, and based on that information decide what further testing, if any, is needed.
No. 12: Changes in the Lymph Nodes
If you notice a lump or swelling in the lymph nodes under your armpit or in your neck -- or anywhere else -- it could be worrisome, Linden says.
"If you have a lymph node that gets progressively larger, and it's [been] longer than a month, see a doctor," she says. Your doctor will examine you and figure out any associated issues (such as infection) that could explain the lymph node enlargement.
If there are none, your doctor will typically order a biopsy.
No. 13: Fever
If you have a feverver that isn't explained by influenza or other infection, it could point to cancer. Fevers more often occur after cancer has spread from its original site, but it can also point to early blood cancers such as leukemia or lymphoma, according to the American Cancer Society.
Other cancer symptoms can include jaundice, or a change in the color of your stool.
Expect your doctor to conduct a careful physical exam and take a medical history, and then order tests such as a chest X-ray, CT scan, MRI, or other tests, depending on the findings
No. 14: FatigueFatigue is another vague symptom that could point to cancer -- as well as a host of other problems. It can set in after the cancer has grown, but it may also occur early in certain cancers, such as leukemia or with some colon or stomach cancers, according to the American Cancer Society.
No. 15: Persistent Cough
Coughs are expected with colds, the flu, allergies, and sometimes are a side effect of medications. But a very prolonged cough -- defined as lasting more than three or four weeks -- should not be ignored, Mishori says.
You would expect your doctor to take a careful history, examine your throat, check out your lung functioning and perhaps order X-rays, especially if you are a smoker
Breast Cancer and the Breast Self-Exam
The most effective way to fight breast cancer is to detect it early. A breast self awareness and self-exam may help, although the most effective tools to detect breast cancer are mammography and clinical breast exam by your health professional. In fact, women who perform regular breast self-exams and learn what is normal find may find abnormalities earlier .
What Is a Breast Self-Exam and Why Should I Do It?
The breast self-exam is a way that you can check your breasts for changes (such as lumps or thickenings), it includes looking at and feeling your breast. Any unusual changes should be reported to your doctor. When breast cancer is detected in its early stages, your chances for surviving the disease are greatly improved. While 80% of all breast lumps are not cancerous, you can help catch potentially serious changes in the breast early by breast self-awareness and by regularly performing a self-exam.
When Should I Perform a Breast Self-Exam?
It is good to start performing breast self-exams in your 20's. If you chose to do breast self-exams, you should examine your breasts regularly , three to five days after your menstrual period ends. If you have stopped menstruating, perform the exam on the same day of each month, such as the first day of the month or a day easy for you to remember, such as your birth date. With each exam, you will become familiar with the contours and feel of your breasts, and will be more alert to changes.
How Do I Perform a Breast Self-Exam?
To perform a breast self-exam, follow the steps described below.
In the mirror:
Stand undressed from the waist up in front of a large mirror in a well-lit room. Look at your breasts. Don't be alarmed if they do not look equal in size or shape. Most women's breasts aren't. With your arms relaxed by your sides, look for any changes in size, shape, or position, or any changes to the skin of the breasts. Look for any skin puckering, dimpling, sores, or discoloration. Inspect your nipples and look for any sores, peeling, or change in the direction of the nipples.
Next, place your hands on your hips and press down firmly to tighten the chest muscles beneath your breasts. Turn from side to side so you can inspect the outer part of your breasts.
Then bend forward toward the mirror. Roll your shoulders and elbows forward to tighten your chest muscles. Your breasts will fall forward. Look for any changes in the shape or contour of your breasts.
Now, clasp your hands behind your head and press your hands forward. Again, turn from side to side to inspect your breasts' outer portions. Remember to inspect the border underneath your breasts. You may need to lift your breasts with your hand to see this area.
Check your nipples for discharge (fluid). Place your thumb and forefinger on the tissue surrounding the nipple and pull outward toward the end of the nipple. Look for any discharge. Repeat on your other breast.
In the shower:
Now, it's time to feel for changes in the breast. It is helpful to have your hands slippery with soap and water. Check for any lumps or thickening in your underarm area. Place your left hand on your hip and reach with your right hand to feel in the left armpit. Repeat on the other side.
Check both sides for lumps or thickenings above and below your collarbone.
With hands soapy, raise one arm behind your head to spread out the breast tissue. Use the flat part of your fingers from the other hand to press gently into the breast. Follow an up-and-down pattern along the breast, moving from bra line to collarbone. Continue the pattern until you have covered the entire breast. Repeat on the other side.
Lying down:
Next, lie down and place a small pillow or folded towel under your right shoulder. Put your right hand behind your head. Place your left hand on the upper portion of your right breast with fingers together and flat. Body lotion may help to make this part of the exam easier.
Think of your breast as a face on a clock. Start at 12 o'clock and move toward 1 o'clock in small circular motions. Continue around the entire circle until you reach 12 o'clock again. Keep your fingers flat and in constant contact with your breast. When the circle is complete, move in one inch toward the nipple and complete another circle around the clock. Continue in this pattern until you've felt the entire breast. Make sure to feel the upper outer areas that extend into your armpit.
Place your fingers flat and directly on top of your nipple. Feel beneath the nipple for any changes. Gently press your nipple inward. It should move easily.
The most effective way to fight breast cancer is to detect it early. A breast self awareness and self-exam may help, although the most effective tools to detect breast cancer are mammography and clinical breast exam by your health professional. In fact, women who perform regular breast self-exams and learn what is normal find may find abnormalities earlier .
What Is a Breast Self-Exam and Why Should I Do It?
The breast self-exam is a way that you can check your breasts for changes (such as lumps or thickenings), it includes looking at and feeling your breast. Any unusual changes should be reported to your doctor. When breast cancer is detected in its early stages, your chances for surviving the disease are greatly improved. While 80% of all breast lumps are not cancerous, you can help catch potentially serious changes in the breast early by breast self-awareness and by regularly performing a self-exam.
When Should I Perform a Breast Self-Exam?
It is good to start performing breast self-exams in your 20's. If you chose to do breast self-exams, you should examine your breasts regularly , three to five days after your menstrual period ends. If you have stopped menstruating, perform the exam on the same day of each month, such as the first day of the month or a day easy for you to remember, such as your birth date. With each exam, you will become familiar with the contours and feel of your breasts, and will be more alert to changes.
How Do I Perform a Breast Self-Exam?
To perform a breast self-exam, follow the steps described below.
In the mirror:
Stand undressed from the waist up in front of a large mirror in a well-lit room. Look at your breasts. Don't be alarmed if they do not look equal in size or shape. Most women's breasts aren't. With your arms relaxed by your sides, look for any changes in size, shape, or position, or any changes to the skin of the breasts. Look for any skin puckering, dimpling, sores, or discoloration. Inspect your nipples and look for any sores, peeling, or change in the direction of the nipples.
Next, place your hands on your hips and press down firmly to tighten the chest muscles beneath your breasts. Turn from side to side so you can inspect the outer part of your breasts.
Then bend forward toward the mirror. Roll your shoulders and elbows forward to tighten your chest muscles. Your breasts will fall forward. Look for any changes in the shape or contour of your breasts.
Now, clasp your hands behind your head and press your hands forward. Again, turn from side to side to inspect your breasts' outer portions. Remember to inspect the border underneath your breasts. You may need to lift your breasts with your hand to see this area.
Check your nipples for discharge (fluid). Place your thumb and forefinger on the tissue surrounding the nipple and pull outward toward the end of the nipple. Look for any discharge. Repeat on your other breast.
In the shower:
Now, it's time to feel for changes in the breast. It is helpful to have your hands slippery with soap and water. Check for any lumps or thickening in your underarm area. Place your left hand on your hip and reach with your right hand to feel in the left armpit. Repeat on the other side.
Check both sides for lumps or thickenings above and below your collarbone.
With hands soapy, raise one arm behind your head to spread out the breast tissue. Use the flat part of your fingers from the other hand to press gently into the breast. Follow an up-and-down pattern along the breast, moving from bra line to collarbone. Continue the pattern until you have covered the entire breast. Repeat on the other side.
Lying down:
Next, lie down and place a small pillow or folded towel under your right shoulder. Put your right hand behind your head. Place your left hand on the upper portion of your right breast with fingers together and flat. Body lotion may help to make this part of the exam easier.
Think of your breast as a face on a clock. Start at 12 o'clock and move toward 1 o'clock in small circular motions. Continue around the entire circle until you reach 12 o'clock again. Keep your fingers flat and in constant contact with your breast. When the circle is complete, move in one inch toward the nipple and complete another circle around the clock. Continue in this pattern until you've felt the entire breast. Make sure to feel the upper outer areas that extend into your armpit.
Place your fingers flat and directly on top of your nipple. Feel beneath the nipple for any changes. Gently press your nipple inward. It should move easily.
source: webMD
10 Lifestyle Tips for cancer prevention
Are you new here? Welcome I take pride introducing myself to you. I am not a medical doctor. However, that does not give me a license to be ignorant about what the doctors are saying about prolonging my life and making more impact in peoples life. Am a motivational speaker majoring on optimum performance technology. I love life and people because without them my world is dead. Here are some powerful tips from the expert on how to keep your body far from the deadly monster called cancer. Enjoy it!
Diet, Activity Recommendations May Reduce the Risk of Cancer, Experts Say
By Miranda HittiWebMD Health News
Reviewed by Louise Chang, MD
Diet, Activity Recommendations May Reduce the Risk of Cancer, Experts Say
By Miranda HittiWebMD Health News
Reviewed by Louise Chang, MD
Oct. 28, 2008 -- Looking for ways to cut your risk of developing cancer? Here's a list of 10 diet and activity recommendations highlighted this week in Chicago at the annual meeting of the American Dietetic Association (ADA).
· Be as lean as possible without becoming underweight.
· Be physically active for at least 30 minutes every day.
· Avoid sugary drinks, and limit consumption of high-calorie foods, especially those low in fiber and rich in fat or added sugar.
· Eat more of a variety of vegetables, fruits, whole grains, and legumes (such as beans).
· Limit consumption of red meats (including beef, pork, and lamb) and avoid processed meats.
· If you drink alcohol, limit your daily intake to two drinks for men and one drink for women.
· Limit consumption of salty foods and food processed with salt (sodium).
· Don't use supplements to try to protect against cancer.
· It's best for mothers to exclusively breastfeed their babies for up to six months and then add other liquids and foods.
· After treatment, cancer survivors should follow the recommendations for cancer prevention.
At the ADA meeting, experts provided practical tips for following those recommendations, which were issued last year by the nonprofit American Institute for Cancer Research and its sister organization, the World Cancer Research Fund International.
Why These Cancer Recommendations?
Walter Willett, MD, DrPH, an epidemiology professor who leads the nutrition department the Harvard School of Public Health, was on the international team of scientists that wrote the recommendations.
At the ADA meeting, Willett said the first recommendation -- to be as lean as possible within the healthy weight range -- is "the most important, by far."
But there is one recommendation that Willett says may be a "mistake" -- the one about not taking supplements. Vitamin D supplements may lower risk of colorectal cancer and perhaps other cancers, notes Willett. He predicts that that recommendation will be a top priority for review.
How to Follow the Recommendations
Karen Collins, MS, RD, CDN, is the nutritional advisor for the American Institute for Cancer Research. She reviewed the recommendations before they were issued last year, and she joined Willett in talking to ADA members.
Collins provides these tips for each of the recommendations:
· Be as lean as possible without becoming underweight: Don't just look at the scale; check your waist measurement as a crude measurement of your abdominal fat, Collins says. She recommends that men's waists be no larger than 37 inches and women's waists be 31.5 inches or less.
· Be physically active for at least 30 minutes every day: You can break that into 10- to 15-minute blocks, and even more activity may be better, notes Collins.
· Avoid sugary drinks and limit consumption of energy-dense foods: It's not that those foods directly cause cancer, but they could blow your calorie budget if you often overindulge, notes Collins, who suggests filling up on fruits, vegetables, and whole grains.
· Eat more of a variety of vegetables, fruits, whole grains, and legumes such as beans: Go for a variety of colors (like deep greens of spinach, deep blues of blueberries, whites of onions and garlic, and so on). Most Americans, says Collins, are stuck in a rut of eating the same three vegetables over and over.
· If consumed at all, limit alcoholic drinks to two for men and one for women per day: Watch your portion size; drinks are often poured liberally, notes Collins. Willett adds that the pros and cons of moderate drinking is something that women may particularly need to consider, weighing the heart benefits and increased breast cancer risk from drinking.
· Limit red meats (beef, pork, lamb) and avoid processed meats: Limit red meats to 18 ounces per week, says Collins, who suggests using chicken, seafood, or legumes in place of red meat. Collins isn't saying to never eat red meat, just do so in moderation.
· Limit consumption of salty foods and foods processed with sodium: Don't go over 2,400 milligrams per day, and use herbs and spices instead, says Collins. She adds that processed foods account for most sodium intake nowadays -- not salt you add when cooking or eating.
· Don't use supplements to protect against cancer: It's not that supplements are bad -- they may be "valuable" apart from cancer prevention, but there isn't evidence that they protect against cancer, except for vitamin D, says Collins.
· It's best for mothers to breastfeed babies exclusively for up to six months and then add other foods and liquids: Hospitals could encourage this more, Collins says.
· After treatment, cancer survivors should follow the recommendations for cancer prevention. Survivors include people undergoing cancer treatment, as well as people who have finished their cancer treatment.
First whooping cough vaccine for adolescents
FDA Consumer, July-August, 2005
In May 2005, the FDA approved the first vaccine for adolescents that provides a booster immunization against whooping cough (pertussis) in combination with tetanus and diphtheria.
Boostrix, a tetanus toxoid (T), reduced diphtheria toxoid (d), and acellular pertussis vaccine (ap) absorbed, will be marketed by GlaxoSmithKline of Philadelphia. Although booster vaccines for adolescents containing T and d are currently licensed and marketed for use in this age group, none contain a pertussis component. Boostrix is indicated for use as a single booster dose to adolescents ages 10 to 18.
Adolescents who received Boostrix experienced pain, redness, and swelling at the injection site. The frequency of redness and swelling after Boostrix was similar to what is expected after the administration of a Td vaccine. Pain reactions at the injection site, however, were more frequent with those who received Boostrix. Other side effects included headaches, fever, and fatigue for a short period of time after injection.
COPYRIGHT 2005 U.S. Government Printing Office
COPYRIGHT 2008 Gale, Cengage Learning
Boostrix, a tetanus toxoid (T), reduced diphtheria toxoid (d), and acellular pertussis vaccine (ap) absorbed, will be marketed by GlaxoSmithKline of Philadelphia. Although booster vaccines for adolescents containing T and d are currently licensed and marketed for use in this age group, none contain a pertussis component. Boostrix is indicated for use as a single booster dose to adolescents ages 10 to 18.
Adolescents who received Boostrix experienced pain, redness, and swelling at the injection site. The frequency of redness and swelling after Boostrix was similar to what is expected after the administration of a Td vaccine. Pain reactions at the injection site, however, were more frequent with those who received Boostrix. Other side effects included headaches, fever, and fatigue for a short period of time after injection.
COPYRIGHT 2005 U.S. Government Printing Office
COPYRIGHT 2008 Gale, Cengage Learning
Wednesday, September 30, 2009
FIRST HIV PREVENTIVE VACCINE SUCCESS: Victory is near
The medical world is agog with great joy as the first vaccine that gives great hope to the prevention and eventual cure of the dreaded monster disease that has held the world captive for some decades now. Here is a special report by Marilynn Marchione, an AP Medical writer Writer.
Scientists and government leaders have already started mapping out how to try to improve the world's first successful AIDS vaccine, which protected one in three people from getting HIV in a large study in Thailand.
That's not good enough for immediate use, researchers say. Yet it is a watershed event in the 26 years since the AIDS virus was discovered. Recent setbacks led many scientists to think a successful vaccine would never be possible.
The World Health Organization and the U.N. agency UNAIDS said the results "instilled new hope" in the field, even though it likely will be years before a vaccine might be widely available.
"This is truly a great moment for world medicine," said Lt. Gen. Eric Schoomaker, the U.S. Army Surgeon General. The Army helped sponsor the study, the world's largest of an AIDS vaccine.
It was the first time scientists tried preventing HIV the same way they treat it — with a combination approach. The study used two vaccines that work in different ways, and that may be one reason the strategy worked, even though neither vaccine did when tested individually in earlier trials, scientists say.
The combo cut the risk of becoming infected with HIV by more than 31 percent in the study of more than 16,000 volunteers in Thailand, researchers announced Thursday in Bangkok.
That benefit is modest, yet "it's the first evidence that we could have a safe and effective preventive vaccine," said Col. Jerome Kim, an Army doctor who helped lead the study.
The outcome "gives me cautious optimism about the possibility of improving this result" and developing a more effective AIDS vaccine, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, which co-sponsored the study.
"It's an opening of a new gateway to a road that has brighter lights in it now and maybe some directions," he said. "We need to bring the best minds together and map the way forward."
That has already started. Dozens of researchers, vaccine makers and deep-pocket donors will meet next week in New York "to talk about where we go from here," said Dr. Alan Bernstein, executive director of the Global HIV Vaccine Enterprise, an alliance of government officials, AIDS scientists, funders such as the Bill & Melinda Gates Foundation, and the WHO. At the meeting will be researchers from the Thai trial, the Army and independent scientists.
Scientists around the world cheered the first taste of victory.
"Since the 1980s, we've been hearing we're going to have an AIDS vaccine in 10 years. For the first time in my lifetime, it feels as though we're actually getting on the right track," said Josh Ruxin, a Columbia University public health specialist who runs the Access Project, which helps health centers provide AIDS care in Rwanda.
The Thailand Ministry of Public Health conducted the study. The U.S. Army has long worked with the Thai government and others to develop and test vaccines and medicine to protect troops and the general public.
The study used strains of HIV common in Thailand. Whether such a vaccine would work against other strains in the U.S., Africa or elsewhere in the world is unknown, scientists stressed.
Even a marginally helpful vaccine could have a big impact. Every day, 7,500 people worldwide are newly infected with HIV; 2 million died of AIDS in 2007, UNAIDS estimates.
The study tested the two-vaccine combination in a "prime-boost" approach, in which the first one primes the immune system to attack HIV and the second one strengthens the response.
They are ALVAC, from Sanofi Pasteur, the vaccine division of French drugmaker Sanofi-Aventis; and AIDSVAX, originally developed by VaxGen Inc. and now held by Global Solutions for Infectious Diseases, a nonprofit founded by some former VaxGen employees.
ALVAC uses canarypox, a bird virus altered so it can't cause human disease, to ferry synthetic versions of three HIV genes into the body. AIDSVAX contains a genetically engineered version of a protein on HIV's surface. The vaccines are not made from whole virus — dead or alive — and cannot cause HIV.
The study tested the combo in HIV-negative Thai men and women aged 18-30 at average risk of becoming infected. Half received four "priming" doses of ALVAC and two "boost" doses of AIDSVAX over six months. The others received dummy shots. No one knew who got what until the study ended.
Participants volunteered for the study and were told about the potential risks associated with receiving the experimental vaccine before agreeing to participate.
All were given condoms, counseling and treatment for any sexually transmitted infections, and were tested every six months for HIV. Any who became infected were given free treatment with antiviral medicines. All participants continued to receive an HIV test every six months for three years after vaccinations ended.
The results: New infections occurred in 51 of the 8,197 given vaccine and in 74 of the 8,198 who received dummy shots. That worked out to a 31 percent lower risk of infection for the vaccine group. Two of the infected participants who received the placebo died.
Scientists don't know why the vaccine combo worked. It was the Army's idea to test the combination, said Dr. Donald Francis, a former government scientist who helped identify HIV as the cause of AIDS and now heads the nonprofit that holds the rights to AIDSVAX.
AIDSVAX is aimed at prompting antibodies to HIV. The Sanofi vaccine spurs cells to attack the virus directly. The combo strategy "bridges the two major arms of the immune system," Francis said.
Scientists need to look at blood samples from study participants to understand why some became infected and others were protected.
"With the limited amount of vaccine we have right now, we've got a small number of studies that we could do," Francis said.
Sanofi officials said the same. The company's Dr. Sanjay Gurunathan said a series of studies "that will take a few years" are planned to see if the vaccine can be improved for licensing, and whether new components should be considered to boost effectiveness.
Even AIDS advocates agreed more research was needed.
"We need to take a deep breath and look at all the available evidence from this trial" before urging that this vaccine be used now, said Julie Davids, a spokeswoman for the Community HIV/AIDS Mobilization Project, a New York-based prevention advocacy group.
The study was done in Thailand because U.S. Army scientists did pivotal research in that country when the AIDS epidemic emerged there, isolating virus strains and providing genetic information on them to vaccine makers. The Thai government also strongly supported the idea of doing the study.
Thailand had a burgeoning AIDS problem when the study began. Aggressive prevention efforts have dramatically cut the rates of new infections there, and only 125 infections occurred in the entire study of more than 16,000 people.
Scientists want to know how long the vaccine's protection will last, whether booster shots will be needed, and whether the vaccine helps prevent infection in gay men and injection drug users, since it was tested mostly in heterosexuals in the Thai trial.
The vaccine had no effect on HIV levels in the blood for those who did become infected. That had been another goal of the study — seeing whether the vaccine could limit damage to the immune system and help keep infected people from developing full-blown AIDS.
That is "one of the most important and intriguing findings of this trial," Fauci said. It suggests the signs scientists have been using to gauge whether a vaccine was actually giving protection may not be valid.
"It is conceivable that we haven't even identified yet" what really shows immunity, which is both "important and humbling" after decades of research, Fauci said.
To view study information click here
FIRST INFLUENZA VACCINE DISCOVERED
INTRODUCTION
Flu vaccine acceptance
According to the CDC: "Influenza vaccination is the primary method for preventing influenza and its severe complications. [...] Vaccination is associated with reductions in influenza-related respiratory illness and physician visits among all age groups, hospitalization and death among persons at high risk, otitis media among children, and work absenteeism among adults. Although influenza vaccination levels increased substantially during the 1990s, further improvements in vaccine coverage levels are needed".[23]
The current egg-based technology for producing influenza vaccine was created in the 1950s.[24] In the U.S. swine flu scare of 1976, President Gerald Ford was confronted with a potential swine flu pandemic. The vaccination program was rushed, yet plagued by delays and public relations problems. Meanwhile, maximum military containment efforts succeeded unexpectedly in confining the new strain to the single army base where it had originated. On that base a number of soldiers fell severely ill, but only one died. The program was canceled, after about 24% of the population had received vaccinations. An excess in deaths of twenty-five over normal annual levels as well as 400 excess hospitalizations, both from Guillain-Barré syndrome, were estimated to have occurred from the vaccination program itself, illustrating that vaccine itself is not free of risks. The result has been cited to stoke lingering doubts about vaccination[25], even though the 24 excess deaths and 400 excess hospitalizations from the 1976 vaccine are dwarfed by the thousands of lives and tens or hundreds of thousands of hospitalizations saved annually by seasonal influenza vaccination.
Current status
Influenza research includes molecular virology, molecular evolution, pathogenesis, host immune responses, genomics, and epidemiology. These help in developing influenza countermeasures such as vaccines, therapies and diagnostic tools. Improved influenza countermeasures require basic research on how viruses enter cells, replicate, mutate, evolve into new strains and induce an immune response. The Influenza Genome Sequencing Project is creating a library of influenza sequences that will help us understand what makes one strain more lethal than another, what genetic determinants most affect immunogenicity, and how the virus evolves over time. Solutions to limitations in current vaccine methods are being researched.
The rapid development, production, and distribution of pandemic influenza vaccines could potentially save millions of lives during an influenza pandemic. Due to the short time frame between identification of a pandemic strain and need for vaccination, researchers are looking at novel technologies for vaccine production that could provide better "real-time" access and be produced more affordably, thereby increasing access for people living in low- and moderate-income countries, where an influenza pandemic may likely originate, such as live attenuated (egg-based or cell-based) technology and recombinant technologies (proteins and virus-like particles).[26] As of July 2009, more than 70 known clinical trials have been completed or are ongoing for pandemic influenza vaccines.[27] In September 2009, the US Food and Drug Administration approved four vaccines against the 2009 H1N1 influenza virus (the current pandemic strain), and expect the initial vaccine lots to be avaialable within the following month.[28]
Clinical trials of vaccines
A vaccine is assessed in terms of the reduction of the risk of disease produced by vaccination, its efficacy. In contrast, in the field, the effectiveness of a vaccine is the practical reduction in risk for an individual when they are vaccinated under real-world conditions.[29] Measuring efficacy of influenza vaccines is relatively simple, as the immune response produced by the vaccine can be assessed in animal models, or the amount of antibody produced in vaccinated people can be measured,[30] or most rigorously, by immunising adult volunteers and then challenging with virulent influenza virus.[31] In studies such as these, influenza vaccines showed high efficacy and produced a protective immune response. For ethical reasons, such challenge studies cannot be performed in the population most at risk from influenza – the elderly and young children. However, studies on the effectiveness of flu vaccines in the real world are uniquely difficult. The vaccine may not be matched to the virus in circulation; virus prevalence varies widely between years, and influenza is often confused with other influenza-like illnesses.[32]
Nevertheless, multiple clinical trials of both live and inactivated influenza vaccines have been performed and their results pooled and analyzed in several recent meta-analyses. Studies on live vaccines have very limited data, but these preparations may be more effective than inactivated vaccines.[31] The meta-analyses examined the efficacy and effectiveness of inactivated vaccines in adults,[33] children,[34] and the elderly.[35][36] In adults, vaccines show high efficacy against the targeted strains, but low effectiveness overall, so the benefits of vaccination are small, with a one-quarter reduction in risk of contracting influenza but no significant effect on the rate of hospitalization.[33] However, the risk of serious complications from influenza is small in adults, so unless the effect from vaccination is large it might not have been detected. In children, vaccines again showed high efficacy, but low effectiveness in preventing "flu-like illness", in children under two the data are extremely limited, but vaccination appeared to confer no measurable benefit.[34] In the elderly, vaccination does not reduce the frequency of influenza, but seems to reduce pneumonia, hospital admission and deaths from influenza or pneumonia.[35][36] However, the measured effectiveness of the vaccine in the elderly varies depending on whether the population studied is in residential care homes, or in the community, with the vaccine appearing more effective in an institution. This apparent effect is unlikely to be real and may be due to selection bias affecting the analysis of the data, or differences in diagnosis and surveillance.
Overall, the benefit of influenza vaccination is clear in the elderly and vaccination of children may be beneficial. Vaccination of adults is not predicted to produce significant improvements in public health. The apparent contradiction between vaccines with high efficacy, but low effectiveness, may reflect the difficulty in diagnosing influenza under clinical conditions and the large number of strains circulating in the population.[32] In contrast, during an influenza pandemic, where a single strain of virus is responsible for illnesses, an effective vaccine could produce a large decrease in the number of cases and be highly effective in controlling an epidemic.[37] However, such a vaccine would have to be produced and distributed rapidly to have maximum effect.[38]
Effectiveness of vaccine
Studies demonstrate that vaccination can be a cost-effective counter-measure to seasonal outbreaks of influenza;[39] but not perfect. A study led by Dr. David K. Shay in February, 2008 reported that
"full immunization against flu provided about a 75 percent effectiveness rate in preventing hospitalizations from influenza complications in the 2005-6 and 2006-7 influenza seasons."[40]
The group most vulnerable to flu, the elderly, is also the least affected by the vaccine, with an average efficacy rate ranging from 40-50% at age 65, and 15-30% past age 70.[41][42][43] There are multiple reasons behind this steep decline in vaccine efficacy, the most common of which are the declining immunological function and frailty associated with advanced age.[44]
In the United States a person aged 50–64 is nearly ten times more likely to die an influenza-associated death than a younger person, and a person over age 65 is over ten times more likely to die an influenza-associated death than the 50–64 age group.[45] Vaccination of those over age 65 reduces influenza-associated death by about 50%.[46][47] However, it is unlikely that the vaccine completely explains the results since elderly people who get vaccinated are probably more healthy and health-conscious than those who do not.[48] Elderly participants randomized to a high-dose group (60 micrograms) had antibody levels 44 to 79 percent higher than did those who received the normal dose of vaccine. Elderly volunteers receiving the higher dose were more likely to achieve protective levels of antibody.[49]
As mortality is also high among infants who contract influenza, the household contacts and caregivers of infants should be vaccinated to reduce the risk of passing an influenza infection to the infant.[50] Data from the years when Japan required annual flu vaccinations for school-aged children indicate that vaccinating children—the group most likely to catch and spread the disease—has a strikingly positive effect on reducing mortality among older people: one life saved for every 420 children who received the flu vaccine.[51] This may be due to herd immunity or to direct causes, such as individual older people not being exposed to influenza. For example, retired grandparents often risk infection by caring for their sick grandchildren in households where the parents can't take time off work or are sick themselves.
In most years (16 of the 19 years before 2007), the flu vaccine strains have been a good match for the circulating strains.[52] In other flu seasons like that of 2007/2008, the match was less useful. But even a mis-matched vaccine can often provide some protection:
...[A]ntibodies made in response to vaccination with one strain of influenza viruses can provide protection against different, but related strains. A less than ideal match may result in reduced vaccine effectiveness against the variant viruses, but it still can provide enough protection to prevent or lessen illness severity and prevent flu-related complications. In addition, it’s important to remember that the influenza vaccine contains three virus strains so the vaccine can also protect against the other two viruses. For these reasons, even during seasons when there is a less than ideal match, CDC continues to recommend influenza vaccination. This is particularly important for people at high risk for serious flu complications and their close contacts.[53]
Comparing flu shot to nasal spray
Flu vaccines are available either as
• TIV (flu shot (injection) of trivalent (three strains; usually A/H1N1, A/H3N2, and B) inactivated (killed) vaccine) or
• LAIV (nasal spray (mist) of live attenuated influenza virus).
TIV works by putting into the bloodstream those parts of three strains of flu virus that the body uses to create antibodies; while LAIV works by infecting a body with a single flu strain that has been genetically modified to minimize symptoms of illness.
LAIV is not recommended for individuals under age 2 or over age 50,[54] but might be comparatively more effective among children over age 2.[55]
A military study on military personnel showed that flu shots yielded less illness than nasal spray. Based on one of the largest head-to-head studies comparing LAIV and TIV (which was conducted by the U.S. Armed Forces Surveillance Center on military personnel who were stationed in the United States during three flu seasons from 2004 through 2007), investigators concluded that: "It may be prudent to use TIV in patients who were vaccinated at least once in the past 2 years [...] but LAIV against pandemic strains maybe be more protective than inactivated vaccines, because the population will probably lack preexisting immunity."[56]
Vaccination recommendations
U.S. Navy personnel receiving influenza vaccination
Various public health organizations, including the World Health Organization, have recommended that yearly influenza vaccination be routinely offered to patients at risk of complications of influenza and those individuals who live with or care for high-risk individuals, including:
• the elderly (UK recommendation is those aged 65 or above)
• patients with chronic lung diseases (asthma, COPD, etc.)
• patients with chronic heart diseases (congenital heart disease, chronic heart failure, ischaemic heart disease)
• patients with chronic liver diseases (including cirrhosis)
• patients with chronic renal diseases (such as the nephrotic syndrome)
• patients who are immunosuppressed (those with HIV or who are receiving drugs to suppress the immune system such as chemotherapy and long-term steroids) and their household contacts
• people who live together in large numbers in an environment where influenza can spread rapidly, such as prisons, nursing homes,schools, and dormitories
• healthcare workers (both to prevent sickness and to prevent spread to patients)[57]
• pregnant women[58][59]
• children from ages six months to two years
Both types of flu vaccines are contraindicated for those with severe allergies to egg proteins and people with a history of Guillain-Barré syndrome.[60]
Side effects
Side effects of the inactivated/dead flu vaccine injection include:
• mild soreness, redness, and swelling where the shot was given
• fever
• aches
These problems usually begin soon after the injection, and last 1–2 days.[61]
Side effects of the activated/live/LAIV flu nasal spray vaccine:
Some children and adolescents 2–17 years of age have reported:[62]
• runny nose, nasal congestion or cough
• fever
• headache and muscle aches
• wheezing
• abdominal pain or occasional vomiting or diarrhea
Some adults 18–49 years of age have reported:[62]
• runny nose or nasal congestion
• sore throat
• cough, chills, tiredness/weakness
• headache
Some injection-based flu vaccines intended for adults in the United States contain thiomersal. Despite some controversy in the media,[63] the World Health Organization has concluded that there is no evidence of toxicity from thimerosal in vaccines and no reason on grounds of safety to change to more-expensive single-dose administration.[64]
The influenza vaccine is an annual vaccine to protect against the highly variable influenza virus[1]. Each injected seasonal influenza vaccine contains three influenza viruses-one A (H3N2) virus, one regular seasonal A (H1N1) virus (not the 2009 H1N1 virus), and one B virus.[2]
`
Purpose and benefits of annual flu vaccination
"Influenza vaccination is the most effective method for preventing influenza virus infection and its potentially severe complications."[3][4][5]
An influenza epidemic emerges during each winter's flu season. Each year there are two flu seasons due to the occurrence of influenza at different times in the Northern and Southern Hemispheres. It is frequently estimated that 36,000 people die each year from influenza and accompanying opportunistic infections and complications in the United States alone.[6] Worldwide, seasonal influenza kills an estimated 250,000 to 500,000 people each year. The majority of deaths in the industrialized world occur in adults age of 65 and over.[7] A review at the NIAID division of the NIH in 2008 concluded that "Seasonal influenza causes more than 200,000 hospitalizations and 41,000 deaths in the U.S. every year, and is the seventh leading cause of death in the U.S."[8] The economic costsin the U.S. have been estimated at over $80 billion.
The number of annual influenza-related hospitalizations is many times the number of deaths.[9] "The high costs of hospitalizing young children for influenza creates a significant economic burden in the United States, underscoring the importance of preventive flu shots for children and the people with whom they have regular contact..."[10]
In Canada, the National Advisory Committee on Immunization, the group that advises the Public Health Agency of Canada, currently recommends that everyone aged 2 to 64 years be encouraged to receive annual influenza vaccination, and that children between the age of six and 24 months, and their household contacts, should be considered a high priority for the flu vaccine.[11]
In the United States, the CDC recommends to clinicians that
In general, anyone who wants to reduce their chances of getting influenza can get vaccinated. Vaccination is especially important for people at higher risk of serious influenza complications or people who live with or care for people at higher risk for serious complications.[12]
Vaccination against influenza is recommended for most members of high-risk groups who would be likely to suffer complications from influenza. Specific recommendations include all children and teenagers, from six months to 18 years of age;[11] [13]
In expanding the new upper age limit to 18 years, the aim is to reduce both the time children and parents lose from visits to pediatricians and missing school and the need for antibiotics for complications ...
An added expected benefit would be indirect — to reduce the number of influenza cases among parents and other household members, and possibly spread to the general community.[14]
In the event of exposure to H5N1-type (avian influenza), seasonal flu vaccine may also offer some protection against H5N1 infection.[15][16][17]
History of the flu vaccine
See also: Timeline of vaccines
Vaccines are used in both humans and nonhumans. Human vaccine is meant unless specifically identified as a veterinary, poultry or livestock vaccine.
Influenza
The first influenza pandemic was recorded in 1580; since this time, various methods have been employed to eradicate its cause.[18] The etiological cause of influenza, the orthomyxoviridae was finally discovered by the Medical Research Council (MRC) of the United Kingdom in 1933.[19]
Known flu pandemics:[20]
• 1889–90 — Asiatic (Russian) Flu, mortality rate said to be 0.75–1 death per 1000 possibly H2N2
• 1900 — Possibly H3N8
• 1918–20 – Spanish Flu, 500 million ill, at least 20–40 million died of H1N1
• 1957–58 – Asian Flu, 1 to 1.5 million died of H2N2
• 1968–69 – Hong Kong Flu, 3/4 to 1 million died of H3N2
•
Flu vaccine origins and development
In the world wide Spanish flu pandemic of 1918, "Physicians tried everything they knew, everything they had ever heard of, from the ancient art of bleeding patients, to administering oxygen, to developing new vaccines and sera (chiefly against what we now call Hemophilus influenzae—a name derived from the fact that it was originally considered the etiological agent—and several types of pneumococci). Only one therapeutic measure, transfusing blood from recovered patients to new victims, showed any hint of success."[21]
In 1931, viral growth in embryonated hens' eggs was discovered, and in the 1940s, the US military developed the first approved inactivated vaccines for influenza, which were used in the Second World War (Baker 2002, Hilleman 2000). Greater advances were made in vaccinology and immunology, and vaccines became safer and mass-produced. Today, thanks to the advances of molecular technology, we are on the verge of making influenza vaccines through the genetic manipulation of influenza genes (Couch 1997, Hilleman 2002).[22]
`
Purpose and benefits of annual flu vaccination
"Influenza vaccination is the most effective method for preventing influenza virus infection and its potentially severe complications."[3][4][5]
An influenza epidemic emerges during each winter's flu season. Each year there are two flu seasons due to the occurrence of influenza at different times in the Northern and Southern Hemispheres. It is frequently estimated that 36,000 people die each year from influenza and accompanying opportunistic infections and complications in the United States alone.[6] Worldwide, seasonal influenza kills an estimated 250,000 to 500,000 people each year. The majority of deaths in the industrialized world occur in adults age of 65 and over.[7] A review at the NIAID division of the NIH in 2008 concluded that "Seasonal influenza causes more than 200,000 hospitalizations and 41,000 deaths in the U.S. every year, and is the seventh leading cause of death in the U.S."[8] The economic costsin the U.S. have been estimated at over $80 billion.
The number of annual influenza-related hospitalizations is many times the number of deaths.[9] "The high costs of hospitalizing young children for influenza creates a significant economic burden in the United States, underscoring the importance of preventive flu shots for children and the people with whom they have regular contact..."[10]
In Canada, the National Advisory Committee on Immunization, the group that advises the Public Health Agency of Canada, currently recommends that everyone aged 2 to 64 years be encouraged to receive annual influenza vaccination, and that children between the age of six and 24 months, and their household contacts, should be considered a high priority for the flu vaccine.[11]
In the United States, the CDC recommends to clinicians that
In general, anyone who wants to reduce their chances of getting influenza can get vaccinated. Vaccination is especially important for people at higher risk of serious influenza complications or people who live with or care for people at higher risk for serious complications.[12]
Vaccination against influenza is recommended for most members of high-risk groups who would be likely to suffer complications from influenza. Specific recommendations include all children and teenagers, from six months to 18 years of age;[11] [13]
In expanding the new upper age limit to 18 years, the aim is to reduce both the time children and parents lose from visits to pediatricians and missing school and the need for antibiotics for complications ...
An added expected benefit would be indirect — to reduce the number of influenza cases among parents and other household members, and possibly spread to the general community.[14]
In the event of exposure to H5N1-type (avian influenza), seasonal flu vaccine may also offer some protection against H5N1 infection.[15][16][17]
History of the flu vaccine
See also: Timeline of vaccines
Vaccines are used in both humans and nonhumans. Human vaccine is meant unless specifically identified as a veterinary, poultry or livestock vaccine.
Influenza
The first influenza pandemic was recorded in 1580; since this time, various methods have been employed to eradicate its cause.[18] The etiological cause of influenza, the orthomyxoviridae was finally discovered by the Medical Research Council (MRC) of the United Kingdom in 1933.[19]
Known flu pandemics:[20]
• 1889–90 — Asiatic (Russian) Flu, mortality rate said to be 0.75–1 death per 1000 possibly H2N2
• 1900 — Possibly H3N8
• 1918–20 – Spanish Flu, 500 million ill, at least 20–40 million died of H1N1
• 1957–58 – Asian Flu, 1 to 1.5 million died of H2N2
• 1968–69 – Hong Kong Flu, 3/4 to 1 million died of H3N2
•
Flu vaccine origins and development
In the world wide Spanish flu pandemic of 1918, "Physicians tried everything they knew, everything they had ever heard of, from the ancient art of bleeding patients, to administering oxygen, to developing new vaccines and sera (chiefly against what we now call Hemophilus influenzae—a name derived from the fact that it was originally considered the etiological agent—and several types of pneumococci). Only one therapeutic measure, transfusing blood from recovered patients to new victims, showed any hint of success."[21]
In 1931, viral growth in embryonated hens' eggs was discovered, and in the 1940s, the US military developed the first approved inactivated vaccines for influenza, which were used in the Second World War (Baker 2002, Hilleman 2000). Greater advances were made in vaccinology and immunology, and vaccines became safer and mass-produced. Today, thanks to the advances of molecular technology, we are on the verge of making influenza vaccines through the genetic manipulation of influenza genes (Couch 1997, Hilleman 2002).[22]
Flu vaccine acceptance
According to the CDC: "Influenza vaccination is the primary method for preventing influenza and its severe complications. [...] Vaccination is associated with reductions in influenza-related respiratory illness and physician visits among all age groups, hospitalization and death among persons at high risk, otitis media among children, and work absenteeism among adults. Although influenza vaccination levels increased substantially during the 1990s, further improvements in vaccine coverage levels are needed".[23]
The current egg-based technology for producing influenza vaccine was created in the 1950s.[24] In the U.S. swine flu scare of 1976, President Gerald Ford was confronted with a potential swine flu pandemic. The vaccination program was rushed, yet plagued by delays and public relations problems. Meanwhile, maximum military containment efforts succeeded unexpectedly in confining the new strain to the single army base where it had originated. On that base a number of soldiers fell severely ill, but only one died. The program was canceled, after about 24% of the population had received vaccinations. An excess in deaths of twenty-five over normal annual levels as well as 400 excess hospitalizations, both from Guillain-Barré syndrome, were estimated to have occurred from the vaccination program itself, illustrating that vaccine itself is not free of risks. The result has been cited to stoke lingering doubts about vaccination[25], even though the 24 excess deaths and 400 excess hospitalizations from the 1976 vaccine are dwarfed by the thousands of lives and tens or hundreds of thousands of hospitalizations saved annually by seasonal influenza vaccination.
Current status
Influenza research includes molecular virology, molecular evolution, pathogenesis, host immune responses, genomics, and epidemiology. These help in developing influenza countermeasures such as vaccines, therapies and diagnostic tools. Improved influenza countermeasures require basic research on how viruses enter cells, replicate, mutate, evolve into new strains and induce an immune response. The Influenza Genome Sequencing Project is creating a library of influenza sequences that will help us understand what makes one strain more lethal than another, what genetic determinants most affect immunogenicity, and how the virus evolves over time. Solutions to limitations in current vaccine methods are being researched.
The rapid development, production, and distribution of pandemic influenza vaccines could potentially save millions of lives during an influenza pandemic. Due to the short time frame between identification of a pandemic strain and need for vaccination, researchers are looking at novel technologies for vaccine production that could provide better "real-time" access and be produced more affordably, thereby increasing access for people living in low- and moderate-income countries, where an influenza pandemic may likely originate, such as live attenuated (egg-based or cell-based) technology and recombinant technologies (proteins and virus-like particles).[26] As of July 2009, more than 70 known clinical trials have been completed or are ongoing for pandemic influenza vaccines.[27] In September 2009, the US Food and Drug Administration approved four vaccines against the 2009 H1N1 influenza virus (the current pandemic strain), and expect the initial vaccine lots to be avaialable within the following month.[28]
Clinical trials of vaccines
A vaccine is assessed in terms of the reduction of the risk of disease produced by vaccination, its efficacy. In contrast, in the field, the effectiveness of a vaccine is the practical reduction in risk for an individual when they are vaccinated under real-world conditions.[29] Measuring efficacy of influenza vaccines is relatively simple, as the immune response produced by the vaccine can be assessed in animal models, or the amount of antibody produced in vaccinated people can be measured,[30] or most rigorously, by immunising adult volunteers and then challenging with virulent influenza virus.[31] In studies such as these, influenza vaccines showed high efficacy and produced a protective immune response. For ethical reasons, such challenge studies cannot be performed in the population most at risk from influenza – the elderly and young children. However, studies on the effectiveness of flu vaccines in the real world are uniquely difficult. The vaccine may not be matched to the virus in circulation; virus prevalence varies widely between years, and influenza is often confused with other influenza-like illnesses.[32]
Nevertheless, multiple clinical trials of both live and inactivated influenza vaccines have been performed and their results pooled and analyzed in several recent meta-analyses. Studies on live vaccines have very limited data, but these preparations may be more effective than inactivated vaccines.[31] The meta-analyses examined the efficacy and effectiveness of inactivated vaccines in adults,[33] children,[34] and the elderly.[35][36] In adults, vaccines show high efficacy against the targeted strains, but low effectiveness overall, so the benefits of vaccination are small, with a one-quarter reduction in risk of contracting influenza but no significant effect on the rate of hospitalization.[33] However, the risk of serious complications from influenza is small in adults, so unless the effect from vaccination is large it might not have been detected. In children, vaccines again showed high efficacy, but low effectiveness in preventing "flu-like illness", in children under two the data are extremely limited, but vaccination appeared to confer no measurable benefit.[34] In the elderly, vaccination does not reduce the frequency of influenza, but seems to reduce pneumonia, hospital admission and deaths from influenza or pneumonia.[35][36] However, the measured effectiveness of the vaccine in the elderly varies depending on whether the population studied is in residential care homes, or in the community, with the vaccine appearing more effective in an institution. This apparent effect is unlikely to be real and may be due to selection bias affecting the analysis of the data, or differences in diagnosis and surveillance.
Overall, the benefit of influenza vaccination is clear in the elderly and vaccination of children may be beneficial. Vaccination of adults is not predicted to produce significant improvements in public health. The apparent contradiction between vaccines with high efficacy, but low effectiveness, may reflect the difficulty in diagnosing influenza under clinical conditions and the large number of strains circulating in the population.[32] In contrast, during an influenza pandemic, where a single strain of virus is responsible for illnesses, an effective vaccine could produce a large decrease in the number of cases and be highly effective in controlling an epidemic.[37] However, such a vaccine would have to be produced and distributed rapidly to have maximum effect.[38]
Effectiveness of vaccine
Studies demonstrate that vaccination can be a cost-effective counter-measure to seasonal outbreaks of influenza;[39] but not perfect. A study led by Dr. David K. Shay in February, 2008 reported that
"full immunization against flu provided about a 75 percent effectiveness rate in preventing hospitalizations from influenza complications in the 2005-6 and 2006-7 influenza seasons."[40]
The group most vulnerable to flu, the elderly, is also the least affected by the vaccine, with an average efficacy rate ranging from 40-50% at age 65, and 15-30% past age 70.[41][42][43] There are multiple reasons behind this steep decline in vaccine efficacy, the most common of which are the declining immunological function and frailty associated with advanced age.[44]
In the United States a person aged 50–64 is nearly ten times more likely to die an influenza-associated death than a younger person, and a person over age 65 is over ten times more likely to die an influenza-associated death than the 50–64 age group.[45] Vaccination of those over age 65 reduces influenza-associated death by about 50%.[46][47] However, it is unlikely that the vaccine completely explains the results since elderly people who get vaccinated are probably more healthy and health-conscious than those who do not.[48] Elderly participants randomized to a high-dose group (60 micrograms) had antibody levels 44 to 79 percent higher than did those who received the normal dose of vaccine. Elderly volunteers receiving the higher dose were more likely to achieve protective levels of antibody.[49]
As mortality is also high among infants who contract influenza, the household contacts and caregivers of infants should be vaccinated to reduce the risk of passing an influenza infection to the infant.[50] Data from the years when Japan required annual flu vaccinations for school-aged children indicate that vaccinating children—the group most likely to catch and spread the disease—has a strikingly positive effect on reducing mortality among older people: one life saved for every 420 children who received the flu vaccine.[51] This may be due to herd immunity or to direct causes, such as individual older people not being exposed to influenza. For example, retired grandparents often risk infection by caring for their sick grandchildren in households where the parents can't take time off work or are sick themselves.
In most years (16 of the 19 years before 2007), the flu vaccine strains have been a good match for the circulating strains.[52] In other flu seasons like that of 2007/2008, the match was less useful. But even a mis-matched vaccine can often provide some protection:
...[A]ntibodies made in response to vaccination with one strain of influenza viruses can provide protection against different, but related strains. A less than ideal match may result in reduced vaccine effectiveness against the variant viruses, but it still can provide enough protection to prevent or lessen illness severity and prevent flu-related complications. In addition, it’s important to remember that the influenza vaccine contains three virus strains so the vaccine can also protect against the other two viruses. For these reasons, even during seasons when there is a less than ideal match, CDC continues to recommend influenza vaccination. This is particularly important for people at high risk for serious flu complications and their close contacts.[53]
Comparing flu shot to nasal spray
Flu vaccines are available either as
• TIV (flu shot (injection) of trivalent (three strains; usually A/H1N1, A/H3N2, and B) inactivated (killed) vaccine) or
• LAIV (nasal spray (mist) of live attenuated influenza virus).
TIV works by putting into the bloodstream those parts of three strains of flu virus that the body uses to create antibodies; while LAIV works by infecting a body with a single flu strain that has been genetically modified to minimize symptoms of illness.
LAIV is not recommended for individuals under age 2 or over age 50,[54] but might be comparatively more effective among children over age 2.[55]
A military study on military personnel showed that flu shots yielded less illness than nasal spray. Based on one of the largest head-to-head studies comparing LAIV and TIV (which was conducted by the U.S. Armed Forces Surveillance Center on military personnel who were stationed in the United States during three flu seasons from 2004 through 2007), investigators concluded that: "It may be prudent to use TIV in patients who were vaccinated at least once in the past 2 years [...] but LAIV against pandemic strains maybe be more protective than inactivated vaccines, because the population will probably lack preexisting immunity."[56]
Vaccination recommendations
U.S. Navy personnel receiving influenza vaccination
Various public health organizations, including the World Health Organization, have recommended that yearly influenza vaccination be routinely offered to patients at risk of complications of influenza and those individuals who live with or care for high-risk individuals, including:
• the elderly (UK recommendation is those aged 65 or above)
• patients with chronic lung diseases (asthma, COPD, etc.)
• patients with chronic heart diseases (congenital heart disease, chronic heart failure, ischaemic heart disease)
• patients with chronic liver diseases (including cirrhosis)
• patients with chronic renal diseases (such as the nephrotic syndrome)
• patients who are immunosuppressed (those with HIV or who are receiving drugs to suppress the immune system such as chemotherapy and long-term steroids) and their household contacts
• people who live together in large numbers in an environment where influenza can spread rapidly, such as prisons, nursing homes,schools, and dormitories
• healthcare workers (both to prevent sickness and to prevent spread to patients)[57]
• pregnant women[58][59]
• children from ages six months to two years
Both types of flu vaccines are contraindicated for those with severe allergies to egg proteins and people with a history of Guillain-Barré syndrome.[60]
Side effects
Side effects of the inactivated/dead flu vaccine injection include:
• mild soreness, redness, and swelling where the shot was given
• fever
• aches
These problems usually begin soon after the injection, and last 1–2 days.[61]
Side effects of the activated/live/LAIV flu nasal spray vaccine:
Some children and adolescents 2–17 years of age have reported:[62]
• runny nose, nasal congestion or cough
• fever
• headache and muscle aches
• wheezing
• abdominal pain or occasional vomiting or diarrhea
Some adults 18–49 years of age have reported:[62]
• runny nose or nasal congestion
• sore throat
• cough, chills, tiredness/weakness
• headache
Some injection-based flu vaccines intended for adults in the United States contain thiomersal. Despite some controversy in the media,[63] the World Health Organization has concluded that there is no evidence of toxicity from thimerosal in vaccines and no reason on grounds of safety to change to more-expensive single-dose administration.[64]
Subscribe to:
Posts (Atom)