Influenza Information
Frequently Asked Questions
Can the flu shot give you the flu? No, a flu shot cannot give you the flu illness. The flu virus in the flu shot are inactivated (killed), which means they cannot cause infection. Manufacturers kill the viruses used in the vaccine during the process of making the vaccine.
Why do some people not feel well after getting the flu shot? Common side effects from the flu shot are soreness at the injection site lasting 2 days. It is caused by the person’s immune system making productive antibodies to the killed viruses in the vaccine. These antibodies are what allow the body to fight against the flu. Rare symptoms include fever, muscle pain, and feelings of discomfort or weakness. These symptoms generally occur soon after the injection and can last from 1-2 days. Treat symptoms with over the counter medications such as Tylenol or Ibuprofen.
What about people who get a seasonal flu vaccination and still get sick with the flu-like symptoms? There are several reasons why this may happen.
- People may be exposed to one of the influenza viruses in the vaccine shortly before getting vaccinated or during the 2 week period of time that it takes the body to gain protection after getting the vaccination.
- People may become ill from the non-flu viruses that circulate during the flu season, which can also cause flu-like symptoms such as rhinovirus. Flu vaccine will not protect a person from respiratory bacterial illnesses that is not caused by the flu virus.
- A person may be exposed to an influenza virus that is very different from the viruses included in the vaccine. The ability of a flu vaccine to protect a person depends largely on the similarity or match between the viruses or virus in the vaccine and those in circulation. There are many influenza viruses.
- Unfortunately, some people can remain unprotected from the flu despite getting the flu vaccine. This is more likely to occur among people that have weakened immune systems or the elderly. However, even among these people, a flu vaccine can still help prevent complications.
Is it too late to get a flu shot? No. Vaccination can still be beneficial as long as influenza viruses are circulating. CDC recommends that providers begin to offer the vaccinations as soon as the vaccine becomes available in the fall, but if you have not been vaccinated you can be protected if you get one later. Seasonal influenza usually peaks in January or February most years, but disease can occur as late as May.
Is the stomach flu really the flu? No. Many people use the term flu to describe illnesses with nausea, vomiting and/or diarrhea. These symptoms can be caused by many different viruses, bacteria or even parasites. While vomiting, diarrhea and being nauseous or sick to your stomach can sometimes be related to the flu, more commonly in children than adults, these problems are rarely the main symptoms of influenza.
