Flu shots would be much less effective than previously thought, a new study revealed.
The team of Michael Osterholm, an infectious disease expert at the University of Minnesota, found that most common flu vaccines in the United States are effective for 59 percent of healthy adults, well below 70 to 90 percent. one hundred previously informed.
“We are stuck with a vaccine that has been around for 60 years and has not changed much,” Osterholm said. The specialist stressed the need for a new generation of flu injections, particularly given the possibility of a pandemic in the future.
There is also a lack of information on how well the vaccine works in children and adults over 65, Osterholm said. These two groups are the ones most at risk of illness or death related to the flu.
US health officials recommend that all Americans older than 6 months get a flu shot.
Nearly 131 million people, or 43 percent of the U.S. population, received the flu vaccine last season, according to the Centers for Disease Control and Prevention (CDC).
Sanofi, GlaxoSmithKline, Novartis, the AstraZeneca MedImmune unit and CSL manufacture doses for the United States market.
While Osterholm does not discuss the need to apply current vaccines, he said that the common perception that they are “good enough” impairs the development of novel therapies.
In a study published in The Lancet Infectious Diseases , the Osterholm team evaluated 5,707 vaccine studies published in the last 40 years.
Experts reduced their analysis to 31 studies that evaluated the presence of influenza in laboratory tests instead of counting the increase in antibodies, a faster method that researchers say often underestimates the effectiveness of the vaccine.
They also limited themselves to analyzing those studies that used randomized controlled trials or other observational methods that did not have “selective bias,” which could lead to the sickest people to be excluded from the research.
A meta-analysis of the 31 studies also showed that a newer type of vaccine, which uses the live virus, had 83 percent effectiveness in protecting children between 6 months and 7 years of age.
However, this type of immunization – manufactured by MedImmune – is not currently recommended as the best treatment for children by the CDC group that decides on immunization practices in the United States, the authors said.
The study was published for a meeting that group will hold on Wednesday.