Personally I think it is impossible to measure, we all know people who get sick with the flu a lot and others who don't know matter what they do. There is no way to prove any vaccines actually work.
Personally I think it is impossible to measure, we all know people who get sick with the flu a lot and others who don't know matter what they do. There is no way to prove any vaccines actually work.
Personally I think it is impossible to measure, we all know people who get sick with the flu a lot and others who don't know matter what they do. There is no way to prove any vaccines actually work.