Influenza Vaccination

(Please note: Initially, I wrote this vaccination information with links to the CDC's website, regarding vaccine information, diseases and surveillance in the United States. However, on February 8th, 2025, the CDC ceased to post new surveillance updates due to the recent directives of the Trump administration. Therefore, the general information should still be applicable but links may be broken and/or outdated).

When to get the flu vaccination: People should get their flu vaccines every year, in the early fall, or otherwise if indicated by the CDC. The CDC estimates about 36,000 annual deaths from the  flu (and pneumonia secondary to flu) in the US. While some people may not care for the CDC, it is probably close. Every year, I see some very sick people from the flu—men and women of all ages. Besides protecting against secondary pneumonia, it also helps protect us against other secondary infections caused by the flu, like meningitis.

From my experience and knowledge, this is typically a very good annual vaccine to get for most people. It typically covers the four most common circulating strains of flu (2 strains of A and 2 strains of B). The strains are determined by scientists who look at the most common circulating strains in other countries where the flu season arrives before influenza hits in the US. From there, they decide on the vaccination that will be needed for our flu season  Sometimes the scientists hit the mark and sometimes not quite. In fact, the flu vaccine is only 40 to 60% effective  Moreover, not everyone has an optimal immune response to the vaccine: Most older people naturally do not produce as many antibodies in response to the vaccine, so they have less protection when exposed to the flu. This would include older people, those with immune compromise, and those with other risk factors. Additionally, the flu shot wears off a little bit each month. According to the University of Minnesota, nearly 6 weeks after the flu shot is given, it starts to wear off by about 9% each month - so becomes weaker as time passes  So, if you are wondering why your flu shot did not work this year, these reasons might explain things  I would still get it because a 50% less chance of getting the flu is better than none.

Overall, the flu vaccination is a pretty well-tolerated vaccine - sometimes a person has a bit of a sore arm or, as mentioned, may feel a little bit ill the day after with a low-grade fever, but nothing like a full-blown flu. If you have any questions about possible reactions to the flu vaccine, discuss it with a healthcare provider before you get it. Also, see contraindications (who should not get a flu shot).

FORMS: IM (Intramuscularly - a flu "shot" and there is also a nasal spray (FluMist [live virus]). The latter can be given to healthy people 2-49 years of age  however, because FluMist is a live vaccine, there are important limitations on who can get this.

Dosage/Strengths: There are also different-strength flu shots for different people. There is a regular-strength quadrivalent vaccine, and there are high-dose vaccines (Fluzone with four times the antigen as the regular dose and effective against four strains) recommended for people 65 and older (who tend to have a less reactive immune response to the regular vaccine). Ask a healthcare provider or a pharmacist which one is right for you.

NOTE: Asmentioned, the flu shot may make you feel a bit "under the weather" for a day or two, but under normal circumstances, it does not give you the flu (I often think of those exposed to those with the flu when they are in a line waiting at their doctor's office or in line at a pharmacy for their flu shot!)

The best times to get a flu vaccination are in September and October. It lasts for approximately six months. A second flu vaccine may be covered after six months "if medically necessary" (vague terminology - In other words, check with your insurance company to be sure it is covered)