Flu shots are grown in chicken eggs. Turns out that flu viruses mutate every year, and the methods we use to make flu vaccines cause them to mutate even more, rendering the flu vaccines less effective. Researchers from Yale recently published on this subject in the Proceedings of the National Academy of Sciences of the United States of America.
We have on known that eggs are not a great way to make vaccines. The process is slow, unwieldy, and prone to errors. Researchers at the University of Pennsylvania (USA) have shown specifically why, with a specific vaccine – last year’s part of the flu vaccine that targeted H3N2 flu virus. You may recall that is the main strain that made folks sick in the USA last year.
First, did the flu vaccine work? According to the Centers for Disease Control and Prevention, last year’s flu vaccine reduced doctors visits for flu by 42 percent. When people were tested specifically for flu strains, the vaccine dropped H3N2 by just 34 percent. Why aren’t the vaccines better, you may ask. Each flu vaccine is a cocktail, aimed at 3 or 4 of the most common flu strains. Unfortunately, the viruses mutate constantly, creating so-called drift and making us aim at a changing target. The second problem is the fact that most of them are grown in eggs.
An influenza virus produced in eggs have to adapt to growing in that environment, hence generating mutations to grow better. The main researcher observes that without such mutations, the virus won’t grow at all. H3N2 grows very poorly in eggs. Now, the Yale researchers have identifies several mutations that occur when the viruses are made in eggs. Still, it is much better for the vast majority of us to get the vaccine than not to get it (unfortunately, fewer than half of us in the USA get one). Finally, there are alternative ways to making the vaccines, rather than using methods developed in the 1940s, but there are many reasons why industry chooses not to do so. I’m Dr. Michael Hunter, and I got my flu shot (mandated by my hospital) last week. Ask your care provider if you should get one too.
I’m Dr. Michael Hunter. Wanna learn more? Click the word Wellness at the top of the page. If you found value in this blog, please go to the comment section and check the follow blog box. Thanks!