These comments are made for the purpose of discussion and should NOT be used as recommendations for or against therapies or other treatments. An individual patient is always advised to consult their own physician.
Flu Shot
Question: I am curious about how fast the flu shot starts to work for example, days, weeks, etc. and are there any side affects to the flu shot?
Thanks
Answer: It is hard to quantify the earliest effective time of onset for influenza vaccine. It seems to have some effect in as little as one week to ten days and has peaked after two to three weeks. It tends to last about four to six months depending on the effectiveness of one’s immune system. Some recommend a second immunization in especially at risk patients; but most people are protected with one shot. Since this is a virus, some people will become mildly “flu-like”; however, this is
exactly the group of people who would be the sickest during a influence outbreak. Usually, the reactions are limited to local redness and pain. There have been cases of neurologic sequelae and seizures in the past; more modern vaccines seem to avoid this risk.
