Just like last season, there may be a partial mismatch in the flu shot this year, suggests early data from the United States, Canada and Britain, the Canadian Press reported.
The vaccine component is meant to protect against influenza B and is actually not a match for that virus strain, which causes the most disease.
Experts must predict each year which strain of influenza B virus will circulate in the coming cold and flu season – they’re usually about 70 percent accurate. Last year, however, they were only about 50 percent accurate at predicting the strain.
Scientists have explored the idea of flu shots being reformulated to add a second B component to the vaccine, which currently protects against one family of B viruses and two A subtypes: H3N2 and H1N1.
The U.S. Centers for Disease Control will meet Monday to discuss their options and present their findings to the Food and Drug Administration in February.
“Historically, it’s obviously been difficult to predict which one’s coming next,” said Dr. Joseph Bresee, the CDC’s chief of influenza surveillance and prevention, about the B virus. “And so one way to hedge those bets is just put them both in the vaccine.”