What about people who get a seasonal flu vaccine and still get sick with flu-like symptoms?

It is still possible to get the flu even if you are vaccinated. This can happen for several reasons: 

  • People may be exposed to an influenza virus shortly before getting vaccinated or during the two-week period it takes the body to gain protection after getting vaccinated. This exposure may result in a person becoming ill with the flu before the vaccine begins to protect them.
  • A person may be exposed to an influenza virus that is not included in the seasonal flu vaccine. There are many different strains of influenza viruses that circulate every year. The flu shot protects against the three or four viruses that research suggests will be most common.
  • Unfortunately, some people can get infected with a a strain of influenza that is covered by the vaccine. Protection provided by the flu vaccine can vary widely, based in part on health and age factors of the person getting vaccinated. In general, the flu vaccine works best among healthy young adults and older children. Some older people and people with certain chronic illnesses may develop less immunity after vaccination. However, even among people who tend to respond less well to vaccination, the flu vaccine can still help prevent influenza. Vaccination is particularly important for people at high risk of serious flu-related complications and for close contacts of high-risk people.
  • Even if you get sick, being vaccinated can help keep symptoms mild and reduce your risk of hospitalization.

Show All Answers

1. What is seasonal flu?
2. How can I protect myself and others from the flu?
3. Who should get vaccinated this season?
4. Can I get a flu vaccine if I recently had COVID-19?
5. How effective is the flu shot?
6. What are the risks from getting a flu shot?
7. What are the side effects that could occur?
8. Can the flu shot give me the flu?
9. Why do some people not feel well after getting the flu shot?
10. What about people who get a seasonal flu vaccine and still get sick with flu-like symptoms?