12:00 Dose of Fluology: Of Urban Legends and Flu Shots

Of Urban Legends and Flu Shots

Seasonal flu shots contain a mixture of 3 strains ("versions"...think of them as dog breeds) of Influenza.  Two are Influenza A variants, and one is an Influenza B.  The variants change from year to year, and are selected based on the best guess of which strains will predominate in any given flu season.  This is often not the same year-to-year, hence the need for an annual shot.  The viruses used to generate the standard vaccine are grown in chicken eggs, purified, killed with formalin, purified again, washed extensively, measured, and then packed into vials for injected vaccines (NOTE: the synthesis and principles here do not apply to FluMist). Let's consider some common features of flu shots:

1.) They are killed.  Ergo, they are not alive.

2.) They are strain-specific.  Ergo, they do not protect against all strains ("versions") of flu.

3.) They are killed with formaldehyde before purification.  Ergo, they do not contain formaldehyde.

4.) They contain flu antigens.  Ergo, they do not prevent you from contacting things that are not the flu.

This is important to point out, since common things said about flu vaccines are:

1a.) "Flu shots give me the flu!"

2a.) "Flu shots don't really protect against flu"

3a.) "Flu shots have formaldehyde in them!!!!!  They're poison!"

4a.) See 2a.  See also, 10:00 dose about what clinical states are not flu (Patients 1 and 2), versus those that are (Patient 3).

So you see, this is not entirely straightforward.  However, what is straightforward is that you have greatly reduced odds of contracting Influenza if you have a gotten a flu shot.