Flu Vaccine 45% Effective This Season, But That’s Better Than It Sounds: CDC

While the flu vaccine is only effective about half the time, federal health officials are stressing the importance of individuals getting the vaccine to protect themselves against the flu and possible complications that may result from the illness.

In a report published this week in the U.S. Centers for Disease Control and Prevention (CDC) Morbidity and Mortality Weekly Report, researchers indicate the flu vaccine is estimated to be about 45% effective for adults and 55% effective in preventing the flu in children this season, which is higher than last year.

The study used data from the U.S. Influenza Vaccine Effectiveness network, including 4,000 children and adults with acute respiratory illness from October 23, 2019, to January 25, 2020.

Flu vaccine effectiveness averages at 40%, so this year’s effectiveness at 45% is an improvement. Especially considering the effectiveness is 50% for children, and 55% for protecting children against the Type A strain that has caused a second wave of flu illnesses, this year’s success is considered high.

Conversely, this season’s vaccine has been ineffective in protecting young adults against the Type A virus. Effectiveness for Type A among young adults has been about 25%, but researchers are unsure why.

So far, there have been at least 92 child flu deaths this year and about 14,000 Americans have died of the flu this season, according to CDC estimates.

New vaccines are made each year and are formulated to protect against three or four different kinds of flu viruses based on what new strains are circulating during that flu season. The vaccines aren’t always on target and effective in preventing the strains most common during a particular season.

Typically, vaccines aren’t considered successful unless they are at least 90% effective. However, that is not the case with the flu vaccine, considering there are many different strains and the virus can evolve quickly.

Despite varying effectiveness of the vaccine, vaccination is still the best way to protect against the flu and its potential serious complications, the CDC advises. The CDC still recommends getting the flu vaccine while flu viruses are circulating in the community.

CDC health experts say getting the vaccine can still prevent illness, hospitalization, and death linked to the current virus, as well as other viruses that may potentially circulate later in the season.