The flu vaccine

MarkAlain Déry, MD, is a physician on staff at Page Hospital.

Question: Should I get a flu vaccine?

Answer: While technically we are well into the flu season, it is still not too late to get vaccinated for the Influenza virus.  Fortunately for Arizona (and a majority of the USA), the flu has been limited mostly to sporadic activity in a few communities.  This is advantageous for those that have yet been vaccinated, as there is still time.  

There are two vaccines, the inactivated (killed) vaccine (the flu shot) that is injected in the muscle and the live attenuated (weakened) vaccine that is sprayed into the nostrils.  The live vaccine while appealing especially to children has yet to be universally adapted due to its cost. 

The following discussion will be limited to the inactivated vaccine.  The killed flu vaccine is made up of different parts of the virus that cause the flu.  Because the entire virus is needed for infection to be successful, it is impossible to get the flu from the flu vaccine.  An analogy of a car is appropriate here; if I gave you the rear view mirror, a tire and the drivers seat of a car and told you to drive to Flagstaff with those parts of the car, it would seem appropriately, absurd.  

The same holds true for the vaccine, because there are only pieces of the virus in the vaccine (as opposed to the whole virus) it is impossible to get the flu from the vaccine.  To be sure, there is a response from the immune system after the vaccine has been given.  This response from the immune system is a complicated cascade of events aimed at stimulating the cells that make antibodies to protect against the flu.  This process involves the release of chemicals that the vaccine recipient interprets as making the recipient feel sick.  Thus, when you experience that feeling of fatigue, body aches and general malaise from the flu vaccine, it actually represents your immune system revving up for antibody production; this fact is appreciated by my patients with HIV/AIDS, when they feel the malaise associated with the vaccine it is an affirmation of their competent immune system. 

Question: Who really needs to be vaccinated for influenza? 

Answer:  Apart from the extremes of ages (the elderly and newly born) and individuals that are immunocompromised, the most important group that needs vaccination are your local health care workers.  They are the ones that are exposed to sick individuals regularly, and while they may not show signs of flu they can still be colonized with the flu virus (have the virus but not show outward signs of infection) and pass it onto others.  In other words, if you go to visit your doctor and he or she has not been vaccinated for the influenza vaccine, your physician (or allied health care worker) can pass the virus onto you thereby needlessly exposing you to an illness that you did not have to get.  Not only does the vaccine prevent the disease, it can also prevent your vaccinated health care worker from passing it on to you. 

As mentioned above, others that should get the flu vaccine include individuals that are advanced in age, especially those that are 65 and older.  The flu affects those that are 65 and older disproportionally than those that are younger than 65; ninety percent of annual flu deaths and more than half of hospitalizations occur in those that are 65 and older.  Despite these grim statistics, only 30 percent of people 65 and older are vaccinated annually for the flu. 

Individuals that have chronic diseases such as asthma, diabetes, kidney diseases or cancer should be proactive for getting the flu vaccine.  Another important group of individuals that should be vaccinated are those with weakened or compromised immune systems from either illnesses such as infection with human immunodeficiency virus (HIV) or hepatitis B or C.  There are certain medicines that can compromise the immune system such as steroids, if an individual is on an immunocompromising drug then they should be vaccinated as well. 

The flu vaccine is safe and effective.  Just as important as preventing the flu, the vaccine can prevent the transmission of virus from those that are colonized with the virus but are asymptomatic to those that are susceptible to disease.