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By Lia Blanchard

The flu season of 2012-13 began early and with a robust virulence. The CDC reports that week 51 of this year, ending on December 22, saw yet another increase in confirmed influenza deaths and hospitalizations, with 31 states reporting “widespread geographic influenza activity”. In an average year, the flu kills about 36,000 Americans, mostly infants under six months old and adults over 65 years of age.

Influenza December 2012

We are well-versed in how to avoid getting or spreading the flu – repeatedly washing our hands, covering our coughs, and most of all, getting vaccinated. But how much do you really know about this virus? Aren’t there many different flu viruses?

H1N1 – H2N3 – Influenza A – Influenza B – What do all of these letters and numbers mean?

There are three subtypes of influenza – A, B, and C. Influenza A is the most dangerous for humans, and C is the least dangerous.

Each subtype is made of a single strand of RNA made with proteins. The most common proteins are hemagglutinin (H – of which there are 16 varieties) and neuraminidase (N – of which there are nine varieties). The various combinations of the different varieties determine the virus’ ability to invade its host.

The swine flu of 2009 is officially called “pandemic influenza A (H1N1) 2009”. The official name includes a year because variations of the H1N1 virus have been tracked for nearly a century, emerging first as the “Spanish flu” pandemic of 1918.

If there so many combinations, how do “they” know what vaccine to make ahead of time?

Vaccine is developed early in the year by scientists who cultivate the current flu virus and observe how it mutates. They compare the results to decades’ worth of previous observations and try to predict how it will “drift” in future months. The vaccine that is developed vaccinates against the three most likely strains/mutations. Just this month it was announced that a four-strain flu vaccine has been approved by the FDA, and will be available for the 2013-14 flu season.

The rapidly changing nature of the influenza virus is why there is a new vaccine every year. Scientists are working toward a universal vaccine that will provide lifetime protection against all strains.

I’m a strong, healthy adult, so why should I get the vaccine? Isn’t this just a money-making method for the pharmaceutical industry?

As a general rule, flu kills only the weakest members of American society, but getting vaccinated is still a good idea for healthy adults. Those whose personal or professional lives put them in contact with the sick, elderly, or very young should be vaccinated to prevent themselves from putting the vulnerable at risk.

At the very least, being sick with the flu will keep you out of work for a few days. Lost productivity and health care costs put the estimated cost of influenza in the USA at $71-167 billion per year.

What is the difference between the traditional shot and the nasal mist?

The injection and nasal spray vaccines use the same formula, protecting against the same three strains of influenza for that year.

Traditional shot: The “flu shot” is made with a “killed” virus and administered via injection. There are three types of injections available:

  1. Regular: for anyone six months or older
  2. High dose: for people 65 and older, believed to provide greater protection
  3. Intradermal: for people 18-64, administered into the skin with a needle 90% smaller than the regular injection needle

Nasal mist: Created with weakened live virus, for healthy people age 2-49, except pregnant women.