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Just the Facts! Debunking Flu Myths with EVCHC

November 20, 2020

Misconceptions about Flu Vaccines

Can a flu vaccine give you flu?

No, flu vaccines cannot cause flu illness. Flu vaccines given with a needle (i.e., flu shots) are made with either inactivated (killed) viruses, or with only a single protein from the flu virus.  The nasal spray vaccine contains live viruses that are attenuated (weakened) so that they will not cause illness.

Is it better to get sick with flu than to get a flu vaccine?

No. Flu can be a serious disease, particularly among young children, older adults, and people with certain chronic health conditions, such as asthma, heart disease or diabetes. Any flu infection can carry a risk of serious complications, hospitalization or death, even among otherwise healthy children and adults. Therefore, getting vaccinated is a safer choice than risking illness to obtain immune protection.

Do I really need a flu vaccine every year?

Yes. CDC recommends a yearly flu vaccine for everyone 6 months of age and older with rare exception. The reason for this is that a person’s immune protection from vaccination declines over time, so an annual vaccination is needed to get the “optimal” or best protection against the flu. Additionally, flu viruses are constantly changing, so the vaccine composition is reviewed each year and updated as needed based on which influenza viruses are making people sick.

Why do some people not feel well after getting a seasonal flu vaccine?

Some people report having mild side effects after flu vaccination. The most common side effects from flu shots are soreness, redness, tenderness or swelling where the shot was given. Low-grade fever, headache and muscle aches also may occur. If these reactions occur, they usually begin soon after vaccination and last 1-2 days. In randomized, blinded studies, where some people got inactivated flu shots and others got salt-water shots, the only differences in symptoms was increased soreness in the arm and redness at the injection site among people who got a flu shot. There were no differences in terms of body aches, fever, cough, runny nose or sore throat.

Side effects from the nasal spray flu vaccine may include: runny nose, wheezing, headache, vomiting, muscle aches, fever, sore throat and cough. If these problems occur, they usually begin soon after vaccination and are mild and short-lived. The most common reactions people have to flu vaccines are considerably less severe than the symptoms caused by actual flu illness.

Does a flu vaccination increase your risk of getting COVID-19?

There is no evidence that getting a flu vaccination increases your risk of getting sick from a coronavirus, like the one that causes COVID-19.

You may have heard about a studyexternal icon published in January 2020 that reported an association between flu vaccination and risk of four commonly circulating seasonal coronaviruses, but not the one that causes COVID-19. This report was later found to be incorrect.

The results from that initial study led researchers in Canada to look at their data to see if they could find similar results in their population. The results from Canada’s studyexternal icon showed that flu vaccination did not increase risk for these seasonal coronaviruses. The Canadian findings highlighted the protective benefits of flu vaccination.

The Canadian researchers also identified a flaw in the methods of the first study, noting that it violated the part of study design that compares vaccination rates among patients with and without flu (test negative design). This flaw led to the incorrect association between flu vaccination and seasonal coronavirus risk. When these researchers reexamined data from the first study using correct methods, they found that flu vaccination did not increase risk for infection with other respiratory viruses, including seasonal coronaviruses.