Why you should be afraid of catching the Flu
Having recently recovered from a bad case of the flu, I got to wondering why they can’t just make a vaccine to take care of it once and for all, like the measles?
It turns out the flu virus is unique in its ability to mutate and adapt, making it impossible to use a single vaccine to combat it. The situation is complicated by the fact that animals, both wild and domestic, are a sort of “mixing bowl” in which new strains of the virus are created.
The variation in the virulence of the flu is apparently due to the varying degrees to which our immune system recognizes the two types of proteins on the surface of the virus -hemagglutinin (H) and neuraminidase (N).
The virus strain is said to undergo “drift” when there are minor changes in the two proteins. This is what happens most years. But sometimes it undergoes a more major change, called “shift,” which is due to reassortment of the viral genes, often when it is mixed with another strain in animals. This is a really bad thing because it means humans will have no antibodies that recognize the new strain, and so no immunity to it.