Question

Flu shots are vaccines against the most common strains of the flu virus. most vaccines are rarely changed but new flu vaccines are produced every year. why are flu shots constantly being reformulated? the flu virus is not completely known.

Answer 1

Answer:

Scientists are creating vaccinations that prevent people from getting bird flu. If the virus mutates, a new vaccine needs to be made. The vaccine needs to be tested, which can be dangerous. It also takes a long time for scientists to know whether the vaccine works

Explanation:

its the sample response

Answer 2

As most people don't take flu shots because later one you develop the flu plus there are symptoms of the shot so yes the flu is not fully known so that's why it's being changed constantly.