I’ve heard a lot of stuff about flu shots. What’s true?

Staying Safe Vaccines

A: There are tons of myths and misconceptions out there about the flu shot. This week, our Friendly Family Doc breaks them down and sets the record straight!

Myth: The flu vaccine causes the flu.

Fact: Nope! There are multiple formulations of the influenza vaccine, both injectable and a nasal spray. Flu shots contain inactive virus or small pieces of the virus and cannot cause the flu. The nasal spray contains live virus that has been attenuated. This means that the virus has been altered to be too weak to cause an infection. This also does not cause the flu.

“But wait!” you may say, I felt sick after getting the flu shot! Mild side effects are common after the flu shot and include low grade fever, sore arm, headaches, and muscle aches. Other than sore arm, the side effects happened at the same rate even when people got a placebo vaccine (the placebo effect is real y’all!). The flu vaccine also takes some time to be effective (up to 2 weeks). If you were exposed to the flu before the flu vaccine kicked in, you can get the flu before you have had a chance to develop an immune response. Of course, your symptoms could also be from a different virus. Many viruses have similar symptoms, like the virus that causes COVID-19. Flu vaccines only protect against the specific strains of influenza included in the vaccine.

Myth: Once I’ve had the flu shot, I can’t get the flu!

Fact: If only! Flu vaccines are about 40-60% effective, depending on the year and how well the vaccine matches the strains of influenza circulating in a community. But do not fret! It is still super important to get the flu vaccine. Flu vaccination reduces your risk of severe illness, hospitalization, and complications from influenza. There is no recommendation for one type of flu vaccine over the other. Pick the one that is licensed for your age and health status and is readily available. Your healthcare providers can help you choose.

Myth: I have an egg allergy so I can’t get the flu vaccine.

Fact: Fortunately, even if you have a severe egg allergy, you can get a flu vaccine. It is true that most available flu vaccines are made by propagating the virus in eggs and may contain very small amounts of egg proteins. People who have mild symptoms (like hives) when they eat eggs can get any flu vaccine that is appropriate for their age and health. People who have severe symptoms of egg allergy can get one of the two vaccines made without eggs (Flublok Quadrivalent or Flucelvax Quadrivalent–if appropriate for their age and health) or they can get any of the vaccines if they are administered in a medical setting. The healthcare team would monitor for symptoms of allergy and be ready to treat if there is a reaction.

Myth: The flu shot is not for me.

Fact: Getting the flu shot is more important than ever. Flu vaccination can help prevent the dreaded “twindemic” of both flu and COVID-19 spreading at the same time. Reducing the risk of flu will help reduce the risk of overwhelming medical resources or catching both at the same time (Fluvid? Coflu? Either way, bad news bears). If you have questions about flu vaccination, talk with your primary care physician.

We also answered this myth in some depth earlier this week: I’m socially distancing, so I don’t need a flu shot this year. Check it out.

This post is a part of our series with a family physician, a proud member of the American Academy of Family Physicians (AAFP).

CDC Info on Flu Shot Misconceptions

Flu Vaccine Effectiveness Info

For full flu vaccine recommendations from the Advisory Committee on Immunization Practices, check out

Info about flu and flu vaccine from the American Academy of Pediatrics

Info about flu and flu vaccine from the American Academy of Family Physicians

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