Study Questions Value of Flu Shots
But many health experts say the vaccine is the best protection against infection
THURSDAY, Oct. 26, 2006 (HealthDay News) -- The flu vaccine is much ado about nothing, according to a new study that contends the annual shots aren't as effective as billed.
"We've got an exaggerated expectation of what vaccines can actually do," said study author Dr. Tom Jefferson, coordinator of the Cochrane Vaccines Field in Rome, Italy. "I'm hoping American and European taxpayers will be alerted and will start asking questions."
He published the findings in the Oct. 28 issue of the British Medical Journal.
Most developed nations and many rapidly developing countries have influenza vaccination programs in place. The programs are believed to reduce the number of cases of flu as well as related hospital admissions and deaths.
In the United States, health authorities recommend that the flu vaccine be given to children aged 6 to 23 months; anyone 50 or older; people with chronic health conditions such as asthma, diabetes, heart disease or HIV; and health-care professionals, caregivers and people who have household contact with individuals at high risk. And for the first time, U.S. health authorities this year are recommending that children aged 23 months to 5 years old also be vaccinated against the flu.
"Recently there's been a real increase in recommendations to prevent what they call influenza with the use of inactivated [dead virus] vaccines," Jefferson said.
For Jefferson, the question is whether such policies are justified.
Previous papers published by Jefferson found that the flu vaccine is only mildly effective in the population for which it is supposedly most critical, the elderly. He also concluded that there is no good science to back new American and Canadian policies of vaccinating children under the age of 2.
For the latest study, Jefferson looked at all the systematic reviews in the world that he could find on the effects of inactivated vaccines. In other words, he looked at published papers that did not generate new data but analyzed existing studies.
"These are reviews of studies, not single studies," he explained. "Systematic reviews are the gold standard for evaluating effectiveness."
Overall, Jefferson concluded, influenza vaccines have little or no effect on many influenza campaign objectives, such as hospital stay, time off work, or death from influenza and its complications.
"I looked at the evidence described by systematic reviews and confronted it with policy and I found that there is a massive gap," Jefferson said. "Almost none of the benefits that these policy documents list are actually given by inactivated vaccines or, if they are, they are given in slighter measure."
Why? He's not sure.
It could be confusion between influenza and influenza-like respiratory illnesses, or inadequate surveillance systems.
"In most surveillance systems, you actually have an almost year-round epidemic which, in fact, is not influenza," Jefferson stated. "It's caused by other agents."
Jefferson also found that many of the existing studies are weak.
But another health expert disagreed with Jefferson's findings.
"The flu vaccine works about 70 to 90 percent of the time in preventing infection in children and young adults and about 40 or 50 percent to 70 percent in the elderly," said Dr. Peter Gross, an influenza expert and chairman of medicine at Hackensack University Medical Center in Hackensack, N.J.
Gross was referring to the body's immune response to the vaccine or whether the vaccine produces enough antibodies to confer protection. "To say that the influenza vaccine is worthless is misleading," he said.
Gross said the evidence is more compelling in favor of flu shots.
"My message is definitely go out there and get the flu vaccine if you're an older individual," Gross advised. "If you're elderly and feel as though you're getting a flu-like illness, speak to a physician to consider an anti-influenza drug because the vaccine is not 100 percent effective in this group."
An estimated 20 percent of Americans get the flu each year. More than 200,000 people are hospitalized from flu complications, and as many as 36,000 die from the infection each year, according to the U.S. Centers for Disease Control and Prevention.
To learn more about the flu vaccine, visit the CDC.