FDA statement on the efficacy of the 2017-2018 influenza vaccine

FDA [to 17 February 2018]

February 15, 2018 –
Statement from FDA Commissioner Scott Gottlieb, M.D. on the efficacy of the 2017-2018 influenza vaccine
Seasonal flu has been widespread this year, impacting millions of people across the country. It has been an especially challenging season, with high rates of hospitalization for both influenza and its complications, which include pneumonia and the exacerbation of chronic conditions such as asthma and congestive heart failure. Many schools have closed in an attempt to control the spread of the illness and doctors’ offices are packed with patients seeking diagnosis and antiviral treatment.

This year much of the illness has been caused by one strain of influenza A called H3N2, with another strain of influenza A called H1N1 and strains of influenza B contributing to lesser extents. The flu is a respiratory illness caused by several types and strains of influenza virus that infect the respiratory tract in humans, which includes the nose, throat and lungs.
Vaccination is one of the best ways known to protect against the flu. However, because of the severity of this season, there have been questions raised about how well this year’s flu vaccine worked. Although the initial report of 36 percent overall efficacy for this year’s vaccine in the United States that has been reported by our colleagues at the U.S. Centers for Disease Control and Prevention (CDC) is better than some might have predicted, there is still clearly significant room for improvement. The FDA is committed to working together with the scientific and medical communities to better protect the public against the flu and apply lessons learned to next season’s flu vaccines.

Because influenza viruses can change their genetic make-up rapidly during the course of a single year, seasonal influenza vaccines are unlike most other preventative vaccines, in that the strains contained in the vaccine constantly need to be adjusted based on the viruses that are expected to be in circulation. Public health experts do their best each year to select the influenza viruses against which the vaccine should provide protection. In fact, in just two weeks, the FDA will be convening an advisory panel of experts to help us select strains for next season’s flu vaccines. It takes several months for influenza vaccines to be produced so flu strains for the next season need to be selected even before the current flu season ends. The majority of vaccine doses are made using chicken eggs, which adds time to the production process, but some doses are made in mammalian cells or by recombinant DNA technology.
Although some factors are beyond our control, such as the ability of flu virus to change rapidly as it circulates, there are steps that we can take to ensure that the seasonal influenza vaccine protects as many individuals as possible. The FDA is collaborating with CDC, the National Institutes of Health (NIH), and other federal partners to address the full spectrum of measures that need to be taken to ensure optimal protection against the flu. These measures include working to select the most appropriate flu strains for inclusion in seasonal influenza vaccines, providing seed viruses and quality control reagents to manufacturers, and ensuring the overall quality of the manufacturing process…