Time for the Flu Shot

Today I rolled up my sleeve for my annual flu shot.  It's a precaution I didn't used to take.

With a wife and two kids in school, I always assumed there was nothing I hadn't been exposed to.  But now that I am (sigh) middle-aged, and presumably more at risk of flu-related illness, I forced myself to go and get immunized at my local Rite Aid today.  It was during my ten minute wait before the shot that a thought occurred to me:  how many strains of flu are there?

According to the Centers for Disease Control and Prevention, there are three types:  A, B, and C.  Type A is the most common, most varied, and most virulent of all of the flu viruses.  There are at least 27 different sub types and strains of the Type A virus, each designated by the type of HA and NA proteins present on the virus's surface.  The H1N1 virus, better known as the Swine Flu virus, made headlines in 2009.

There are also Type B and Type C flu viruses.  Both are less common and somewhat less dangerous than the viruses in the Type A family.

Helping protect us against the flu is the influenza vaccine.  Each dose contains three influenza viruses:  two Type A and one Type B, based on the World Health Organization's flu forecast.  According to Wikipedia, the 2011-2012 flu shot is composed of vaccines against...

• an A/California/7/2009 (H1N1)-like virus;
• an A/Perth/16/2009 (H3N2)-like virus;
• a B/Brisbane/60/2008-like virus

It's the same formula as last year.

Each immunization should provide a lifetime of immunity against the strains of flu in each shot, assuming the viruses don't mutate.  And influenza is one of the those pesky viruses, like the cold virus, which is always remaking itself, forcing our immune systems to adapt and forcing us to get a new flu shot every year.

The CDC recommends flu shots for the very young, senior citizens, and those with compromised immune systems.  But experts say that everyone can benefit from having a flu shot.  Studies have shown immunizations greatly reduce hospitalization rates due to flu.

The flu is more than just a fever and chills, doctors say.  The National Institutes of Health has estimated more than 200,000 Americans are hospitalized every year due to the flu; more than 40,000 Americans die from it.

The U.S. should have a solid supply of flu vaccine this year.  The CDC estimates more than 160 million doses will be available.  Flu shots are available at your doctor's office, local health departments, most pharmacies and even some grocery stores.

Links:
CDC report on flu strains
CDC report on flu shot supply
Wikipedia article on flu shots