But nobody wants to get a shot that might be unnecessary or ineffective, either. So, while some experts worry aloud about a 1918-like flu pandemic, most of uswell aware of the risks of getting the virus, from being sneezed on at the office to living with a toddlerare not lining up to get the shot. In fact, only a third of us even bother. The truth is, while the U.S. Centers for Disease Control and Prevention (CDC) and most mainstream docs are pushing the flu vaccine, the latest science suggests it just doesnt work very well. So, should you or shouldnt you? Here, the answers to your flu-shot questions.
How effective is the shot?
The flu shot is only as good as the educated guesses of a group of vaccine researchers across the globe. Every February, they try to predict which flu viruses will work their evil during the next fall and winter. Their three top choices are put into the vaccine. The CDC claims that vaccine will be 70 to 90 percent effective against just those strains of flu. “We hope that these smart scientists who get together with the vaccine producers make the right call,” says immunologist Randy Horwitz, MD, medical director of the University of Arizonas School for Integrative Medicine. But sometimes they dont, partly because the virus mutates from year to year. In 2003–2004, the CDC admitted that it completely missed the virulent Fujian flu strain that hit hard that winter.
In 2005–2006 season, in which the CDC said the match between the vaccine and the virus was good, a strain not included in the vaccine hospitalized 31 children in Houston. Also, two recent studies found that the shot may be less effective for people with weaker immune systems, so its effectiveness can depend on how well your body responds to the vaccine.
Will it make me sick?
Even if it doesnt work, it cant hurt to get the shot, right? For most people that may be true. Millions of vaccinations are administered each year, but since 1991, only about 26,000 adverse events have been reported to the Vaccine Adverse Events Reporting System (VAERS). Most of those were fever, rash, headaches, hives, or, very rarely, seizures. The most common side effect is swelling at the injection site on your arm. And any bad reactions, thought to be your immune systems way of gearing up after the exposure to dead virus particles in the vaccine, typically ease after a few days. (Manufacturers are required to verify that each batch of vaccine used for injections contains no live flu viruses. But people with egg allergies shouldnt get the shot because the vaccine is manufactured using eggs.)
Still, some researchers arent comfortable with the safety data. Tom Jefferson, MD, coordinator of the Vaccines Field for the Cochrane Collaborative, an international group of researchers, reported last year in the British Medical Journal that he had found only six limited studies on safety after reviewing 206 studies on the vaccine. That, he says, is a surprisingly small number considering the widespread use of the vaccine and its mixed bag of ingredients.
Osteopathic doctor Sherri Tenpenny, author of VaccinesThe Risks, the Benefits, the Choices: A Resource Guide for Parents, cautions that only small populations and short-term info are used to measure safety. Adverse-events reporting, for instance, is done for only 2 to 14 days after an injectionand its voluntary.
Heres another concern: Except for about 8 million doses, the flu vaccine contains a preservative, thimerosal, that is 49 percent mercury, a known neurotoxin. While the latest research seems to disprove any link between thimerosal vaccines and autism in children, the debate still rages, and several states have prohibited the use of thimerosal in childrens vaccines. Yet supplies of mercury-free flu vaccine are limited due to man-ufacturing capacity. If you want to avoid thimerosal, you may have to make a special request to your health-care provider in advance.