The Maltese Influenza: A True Flu Noir

Antigenic drift is one of the reasons that scientists have to cook up a new flu vaccine each year. They need to approximate what the new flu of the year is going to look like, although (like Max the Vacc with his slightly outdated mug shots) sometimes they can’t predict exactly what the most prevalent virus will be. Consequently, some years the flu vaccine is more protective than in other years, i.e. the vaccine is a closer match to the actual flu virus that turns out to be the major contributor to disease that year.

What about pandemic flu, you ask? It results from a slightly different process known as antigenic shift. Antigenic shift, which may be much more sudden than antigenic drift, occurs when the segments of the human flu virus re-assort and attach to segments of animal viruses—think swine flu, bird flu, and so on. (I couldn’t think of a tasteful G-rated way to include antigenic shift in my little noir anecdote—any references to bestiality wouldn’t have gotten past the censor in the 1940s. [Ed: Or in PopSci today, for that matter.])

Anyway, what everyone always wants to know is whether you can actually get the flu from the flu vaccine. The answer is “no”—the standard vaccine (with the needle) is made from killed virus; there is no way for the dead virus to give you the flu. The nasal spray vaccine, which is available for certain people without other health conditions, is made from attenuated virus, which means the virus is weak, too weak to actually give you the flu. After either vaccine, some people may feel achy and feverish for a day or two, but this is just your immune system revving up in case it needs to recognize the real flu in the future. Most people feel fine, and those who feel lousy get better in a day or two.

So if your doctor offers you a flu shot—go for it. A season’s worth of protection from disease is nothing to sneeze at.