Each year, researchers track strains of influenza as they de…
Each year, researchers track strains of influenza as they develop an updated influenza vaccine. In recent years, this vaccine has been a quadrivalent one, i.e., one containing antigens targeting four influenza strains (two type A and two type B influenza viruses), although for the 2024-2025 season, the influenza B/Yamagata strain has been dropped from the vaccine (this is because we have not detected it since March 2020, and we believe we have driven it to extinction as a result of non-pharmaceutical interventions implemented at the start of the COVID pandemic – i.e., a happy victory for humans!) In addition to the possibility of changing strains based on their prevalence, researchers update the specific antigens for each strain involved. This is because even if a strain included last year is still a dominant one this year, it will have undergone sufficient ______ via the accumulation of point mutations that the effectiveness of our immune response from last year will not be as protective this year. Copyright 2025 by Dr. Jonathan A. Miller. All rights reserved. Online sharing or distribution is prohibited. For exam use only in BIOL& 260: Microbiology at Edmonds College. Outside help is not allowed.