Optimal Time of Flu Shot: Influenza B Is the Problem

摘要

A trivalent influenza vaccine (TIV) contains hemagglutinin derived from strains of an A (H3N2)-like virus, an A (H1N1)pdm09-like virus, and a B (either Victoria or Yamagata lineage)-like virus. A quadrivalent influenza vaccine (QIV) contains an additional B strain which is not included in the TIV. On the basis of the experts' review of surveillance data available and their discussion on the candidate vaccine strains, the World Health Organization (WHO) recommends the composition of Northern Hemisphere influenza vaccines, i.e., which strains should be included in the vaccines. Although the prediction might make a good hit, as the antibody titer wanes and if it is not protective at the time of the epidemic, all the efforts for the influenza vaccination end in failure.