Can I Get the Flu from the Vaccine & Other FAQ

By Aimée Kahn, M.D., MPH November 3, 2016

Four frequently asked questions about the flu vaccine

Can I get the flu from the flu shot?

This is a common misconception regarding vaccination with the influenza vaccine (flu shot), so let’s clear the air. The influenza vaccine that’s given by an injection (shot) does not contain any living virus. To make the vaccine, the virus is heated and inactivated (killed) prior to testing by the U.S. Food and Drug Administration. This means the virus cannot infect you and cause you to have the flu infection.

What can happen, though, is one person may have an illness brewing around the same time as getting the vaccine. Then, that same person feels worse after the flu shot and assumes it is the flu. But again, this is not possible because the flu shot does not have a live virus able to infect you—so you are safe. The protection from the vaccine takes approximately two weeks to start working. If you’re exposed to the flu virus within two weeks of receiving the vaccine, you are not yet fully protected from it and you could get sick. The most common side effects of getting the vaccine are soreness at the site of injection, headache, and muscle ache—which only last one to two days.

Who should get the flu vaccine?

The influenza vaccine is recommended for all people ages 6 months and older, and for those caring for infants who are younger than 6 months. The best way to protect newborns younger than 6 months from the flu is for caregivers to get vaccinated. Also, all pregnant mothers are at a higher risk of getting sicker from the flu than others and are recommended to get the influenza vaccine during pregnancy. This not only offers protection from the flu for the mother, but for the newborn as well for several months after birth. In addition, if you have a serious anaphylactic allergy to eggs, talk to your doctor about this before getting the influenza vaccine.

I hate needles; is there another way to get the vaccine?

The influenza vaccine is available in two forms: an injection (shot) and nasal spray. The nasal spray does contain a live vaccine, however, the virus is weakened and then tested by the FDA. Unfortunately, during the 2016-2017 flu season, the nasal spray is not recommended as per the Centers for Disease Control and Prevention and the American Academy of Pediatrics.

But do I really need to get the flu vaccine?

There are many benefits to getting the influenza vaccine. The flu vaccine can prevent you from getting sick from the flu. Vaccination also reduces the chances of flu-related hospitalizations from complications of the infection. As mentioned, vaccination during pregnancy protects the mother and her newborn, which is especially important as babies’ immune systems are not as strong as those older and can have much worse outcomes with infection. Though attempted, it is impossible for the vaccine to cover every single strain of the influenza virus that can infect an individual. If you’re infected but have gotten the flu shot, your symptoms will be milder and not as severe as if you are unvaccinated. Getting the vaccine reduces the chances that you will get the flu and that you will not pass it on to others.

Catching the flu can cause a very serious illness that can result in hospitalization and even death. Every year, nearly 100 children die in the U.S. from complications of getting the flu. Young children and individuals older than 65 are more likely to have worse symptoms from the infection than others. Symptoms of the flu include fever, cough, sore throat, muscle aches and headaches, nasal congestion, and feeling tired. Children are more likely to also have vomiting and diarrhea associated with the infection, compared to older age groups. You’re most likely to spread the infection one day before symptoms start and up to a week or more after. If you’re feeling these symptoms, believe your child is, or need to get the flu shot, see your primary care doctor or pediatrician.