I don’t know about you, but it seems everywhere I look lately there are advertisements for the flu shot.  CVS, Rite Aid, Walgreens…even Target and WalMart are promising to provide you with the vaccine “in 15 minutes or less without a trip to your doctor.”  

When I got pregnant last fall it was treated as a matter of course that I receive my vaccine for the protection of my unborn baby.  And, now this fall, because my daughter Elliot is only 4 months old, its the same story…vaccinate yourself to protect your child (who is incidentally too young to get the flu vaccine, but when it comes to the multitude of other vaccines there is no age restriction – but more on that later!).

But is this vaccine as necessary as our local pharmacies would like us to believe?  And, does it really offer the protection it promises from the flu?

What is the Flu shot?

The flu shot is an annually administered vaccine designed to protect you from the seasonal flu.  It can be given as an intramuscular injection which contains a “dead” virus, or as an intranasal mist containing a “live” virus.

What many people don’t realize is that the seasonal flu shot is different each year and each vaccine contains 3 different strains of the influenza virus.  The 3 virus strains that are chosen are the three influenza viruses that research indicates will be most common during the upcoming season.  However, over the course of the flu season (October to May), many different influenza viruses can circulate at different times and in different places.

How does the Flu shot work?

The flu vaccine, like all vaccines, introduces a known pathogen into the body for the express purpose of creating antibodies against that pathogen.  The presence of antibodies creates future protection against that particular disease.

When a vaccine is administered either a small amount of pathogen, a less virulent version, or a killed version of a pathogen is introduced into the body.  The immune system launches an attack and creates antibodies to destroy what has been introduced to the body in the vaccine.  Because only a small amount, a very weak, or dead form of the pathogen is present, the immune system has (almost) no trouble defeating the intruder and you (almost) never get sick from the vaccine.

Many of the vaccines we receive as either children or adults are for what are known as stable viruses.  This means the DNA or RNA of these viruses changes very little over time.  The more stable the virus, the more effective the vaccine.  The influenza virus, however, is not at all stable.  It can mutate very quickly and can even borrow genetic material from the influenza viruses of different animals, namely pigs and birds.  Yup, you heard me – pigs and birds…that is where the names swine and avian flu come from.  Human, pig and bird flu can easily exchange genetic material because they are so similar.  In places like SouthEast Asia where people, pigs, and birds live in close proximity, these viruses readily exchange genetic information.  These places are also where the seasonal flu is “born”.

But even without the help of pig or bird DNA, the influenza virus will mutate over the course of the flu season.  Often the virus that causes illnesses at the start of the flu season is not genetically identical to the virus causing illness at the end of it.  According to the CDC, the ability of a flu vaccine to protect a person depends on 2 factors:

1. the age and health status of the person getting the vaccine
2. the similarity or “match” between the viruses or virus in the vaccine and those in circulation.

Get a flu vaccine for the wrong flu virus and its like you’ve received no vaccine at all.  This was exactly the case during the 2003-2004 flu season when the CDC announced that the administered flu vaccine that season had “no or low effectiveness” against influenza or influenza-like illness because it was not a genetic match.

And there is no way to predict how the virus will mutate over the course of the flu season. Doesn’t sound very promising, does it?

Stay tuned for Part 2 to learn how the flu shot is made (if the effect of unpredictibility of the flu virus didnt make you think twice about the vaccine, perhaps this will…) and what you can do to REALLY protect yourself!

 

Related articles

• Flu season has arrived, so have the shots (nbc-2.com)