Do I Really Need a Flu Vaccine This Year?
It’s September and flu season will soon be upon us. Each year people ask if they need another flu vaccine. The answer is no – as long as you are willing to be miserably ill for 5-10 days; to spread disease to your family, friends, co-workers, and anyone else you meet; and to possibly die! If none of that sounds appealing, then definitely get a vaccination as it will reduce your chance of illness and death. Being protected by vaccination will also contribute to herd immunity and help prevent the dissemination of this disease in your community. The CDC recommends that everyone 6 months and older receive a yearly flu shot.
The Centers for Disease Control (CDC) estimates that each year in the US since 2010 there have been an average of 28.5 million flu cases, 13 million medical visits, 475,000 hospitalizations, and 42,000 deaths. That’s an average of 115 people a day dying of influenza, day in and day out, year after year. More people in this country die of flu than are killed each year by traffic accidents. Most of these flu-related deaths could have been prevented with vaccination, yet vaccination rates in adults hover only around 40%. In contrast, nearly 85% of Americans regularly wear seat belts to reduce crash injuries and death.
People also ask why they have to get a flu shot every year when for other diseases they get 1-3 shots and are protected for decades. The answer is that the influenza virus mutates very rapidly. These mutations change the viral surface proteins so that our antibodies can no longer recognize the virus. Each year the vaccine raises antibodies against the surface proteins of what we hope are the most prevalent forms of flu virus in circulation. [You may notice that the vaccine you receive is trivalent (against 3 strains of flu) or quadrivalent (against 4 strains)]. If you get exposed to these strains then the antibodies bind to the virus and “neutralize” it so that it can’t infect your cells and cause disease. However, by next year the surface proteins may have changed so much that last year’s antibodies no longer recognize and neutralize the current strains. The only solution so far is to get a new vaccine each year against that year’s most likely strains. The vaccine manufacturers try to predict what the upcoming strains will be and produce an effective vaccine, but it’s never as effective as vaccines against viruses that don’t change from year to year. Typically the flu vaccines have an effectiveness around 40%, compared to most other viral vaccines whose effectiveness is greater than 90%. Even 40% effectiveness still goes a long way towards preventing disease, reducing disease severity if you are infected, and helping stop the virus spread in communities. The good news is that researchers are inching closer to a more universal flu vaccine that may be able to provide broader and more long lasting immunity than the current vaccines.
Finally, I’ve heard people say they no longer take the vaccination because one time they got vaccinated and it gave them the flu. That’s really not possible since the vaccine injected into the arm is an inactivated or “killed vaccine”. Such vaccines can’t cause an infection or disease. People think the vaccine gave them the flu because of a coincidence of timing. The vaccine takes about a week to generate protective antibodies. If you were exposed to the flu anytime in the week prior to or the week following vaccination you are still likely to get the flu because the protective effects of the vaccine haven’t yet kicked in. The timing makes you think you got ill from the vaccine, but you really got sick from a community acquired infection, just like someone who hadn’t been vaccinated. Mild side effects are possible from the flu vaccine, including soreness, redness, and/or swelling at the injection site, headache, mild fever, nausea, and muscle aches. People sometimes mistake these symptoms for flu, but all of these should be fairly transient and nothing like getting the actual flu. Also, since the vaccine virus is grown in eggs, people with egg allergies may have an allergic reaction. However, the CDC recommends that individuals with egg allergies simply receive the vaccine in a clinic or similar medical environment where any allergic reaction can be quickly treated. Alternatively, there is an egg-free version of the flu shot available called Flucelvax. So don’t let vaccine fear prevent you from getting this important protection. Contact your doctor for questions or concerns.