Symptoms of influenza usually appear 1-4 days after exposure. How long can a person spread influenza? Persons are most contagious during the 24 hours before symptoms appear and may be contagious for up to 5 -7 days after getting sick.
Likewise, why do I get sick after getting a flu shot?
The viruses in the flu shot are killed, so people cannot get the flu from a flu vaccine. However, because it takes about two weeks for people to build up immunity after they get the flu vaccine, some people may catch the flu shortly after their vaccinated, if they are exposed to the flu during this time period.
What are the side effects of the flu shot?
Common side effects from the flu shot include:
- Soreness, redness, and/or swelling from the shot.
- Muscle aches.
Can you get a cold from the flu shot?
MYTH: You can catch the flu from the vaccine. The vaccine is made from an inactivated virus that can't transmit infection. So people who get sick after receiving a flu vaccination were going to get sick anyway. But people assume that because they got sick after getting the vaccine, the shot caused their illness.