Current vaccines are not as protective against influenza as public-health messages suggest — a factor that is holding back efforts to develop truly effective and “game-changing” flu vaccines, according to a comprehensive report released Monday by researchers at the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP).
After spending three years reviewing more than 12,000 studies, scientific papers, meeting summaries and other documents dating back to 1936 and interviewing 88 influenza-vaccine experts, the CIDRAP researchers found that protection from the current influenza vaccine is “suboptimal.”
“We can no longer accept the status quo regarding vaccine research and development,” said CIDRAP Director Michael Osterholm as he read from the report’s preface at a press conference on Monday.
Limited protection
The vaccine-effectiveness figures cited in the report are basically the same as those published a year ago by CIDRAP in the journal Lancet Infectious Diseases. Eight more recently published studies were added to the 31 used in the Lancet analysis for the current report, but those additional studies did not change the overall findings (which I reported here last fall):
- The trivalent inactivated vaccine (TIV), or “flu shot,” offers at best a 59 percent protection against influenza in healthy adults aged 18 to 64. The evidence is inconsistent regarding protection for children aged 8 to 17 and poor for adults aged 65 years and older.
- The live attenuated influenza vaccine (LAIV), or nasal-spray vaccine, has an efficacy of 83 percent in children aged 6 months to 7 years. The evidence is inconsistent regarding protection for adults aged 60 and older and nonexistent for people aged 8 to 59.
Recommendations in recent years to expand the groups that receive the annual influenza vaccine were often, therefore, “based on professional judgment and not on scientifically sound data,” according to the new report.
To save more lives — particularly from influenza pandemics — the government should be encouraging pharmaceutical companies to develop new, “game-changing” vaccines rather than simply improve current ones, the report says. Right now, the report notes, companies have little financial incentive to take the risk to try an entirely different approach to vaccine development.
A major obstacle to trying new approaches, the report stresses, is the mistaken belief that current flu vaccines are highly effective.
Safety ‘not an issue’
At the press conference, Osterholm emphasized that during his and his co-authors’ exhaustive review of the scientific literature, they found “no reason to believe that [the flu vaccine] provides any harm whatsoever.”
“Safety is not an issue,” he said.
He also stressed that although the vaccine is not as effective as the medical community generally believes, it still offers some protection against the flu.
“We continue to urge people to get vaccinated,” he said, adding that he has already received his flu shot for the year.
The Centers for Disease Control and Prevention currently recommends that almost everybody aged six months and older be inoculated each year against influenza with either the TIV jab-in-the-arm flu shot or the LAIV nasal-spray form of the vaccine. (Among the exceptions are people with allergies to eggs and individuals with the neurological disorder Guillain-Barre syndrome.)
Each year an estimated 3,000 to 49,000 Americans die from seasonal influenza, according to government figures. Children under the age of five, adults over the age of 65, and individuals with asthma, heart disease, diabetes, HIV/AIDS and other chronic diseases are the most likely to develop serious complications from the flu.
You can download and read the entire CIDRAP report from the organization’s website. The report was funded in part from the Alfred P. Sloan Foundation.