inspire_rainbows t1_iwpmu3f wrote on November 17, 2022 at 12:20 PM

Many years ago there was a 60 Minutes type programme discussing how the flu vaccine is made. The gist of it was there are many, many flus at any given time on the earth and trying to pick which one(s) were going to come to your area of earth was, basically, a guessing game. This is why, during some years, the flu vaccine was ineffective because the ‘wrong’ flu was picked. Is this still an issue or has our ability to track and predict flu patterns better thereby making the flu vaccine more accurate?

haley_bridgewater t1_iwr91ik wrote on November 17, 2022 at 7:21 PM

Influenza is a tricky virus to vaccinate against because it rapidly mutates and has multiple strains circulating in one year. Our ability to predict these strains is improving, but it is still a prediction. We are improving the number of strains we can vaccinate against. The first influenza vaccine only vaccinated against H1N1, where as this years influenza vaccine protects against 4 strains.

inspire_rainbows t1_iwro0c5 wrote on November 17, 2022 at 9:00 PM

Thanks for your time. I do appreciate this thread and the answers.

FluFighterDrJB t1_iwr8amd wrote on November 17, 2022 at 7:17 PM

Due to a process called ‘antigenic drift’, influenza viruses are constantly changing as they circulate within a population (read more at: https://www.cdc.gov/flu/about/viruses/change.htm ). The standard inactivated influenza vaccine includes multiple different subtypes of virus (from H1N1, H3N2, and influenza B viruses) and each component can change in this manner. And yes, due to manufacturing timelines, the decision of which specific virus to include in the vaccine takes place months before you actually receive the vaccine in a clinic (see Figure 1 in this publication for an example of the timeline: https://onlinelibrary.wiley.com/doi/full/10.1111/irv.12383 ). There are intense efforts underway trying to move towards ‘universal’ influenza vaccines (in other words, targeting parts of the influenza virus in the vaccine that are not subjected to antigenic drift), though this approach represents a challenging undertaking for several reasons (summarized in https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6028071/ ).