Question: is this year's flu shot effective against influenza b?
Answer: According to a Feb. 21 CDC Morbidity and Mortality Weekly Report, the current influenza vaccine has been 45% effective overall against 2019-2020 seasonal influenza A and B viruses. Specifically, the flu vaccine has been 50% effective against influenza B/Victoria viruses and 37% effective against influenza A(H1N1)pdm09.