what is different about the flu vaccine from year to year?

Answer 1

There are thousands of different strands of the flu virus. We are basically putting our health in the hands of the Dr's and Scientists at the CDC and WHO. They make an educated prediction based on current situations and previous years flu as to which strands will be the problem each year. Each year the vaccine contains vaccination for only the 3 most prominent strands. They just hope they are right and that a different strand does not become more evident. It is still wise to get the shot, though.

Answer 2

When ramping up for the next year's flu vaccine, scientists choose the most likely strains of the virus that will affect your area and prepare a vaccine that will protect against those strains. What was thought to be a good candidate last year may not even be considered this year.

Answer 3

O.K. I'm not a scientist but as I understand it, each year vaccines are created based on the most recent strain(s) of flu which, clever germ that it is, keeps changing (think of swine flu, bird flu and so on...). That's why last year's vaccine won't necessarily work against this year's flu. But there's no guarantee that an even newer strain won't pop up before there's an appropriate vaccine.
The best thing you can do is take care of yourself:eat healthily, get enough rest, dress warm, wash your hands a lot (! -- evidently more colds are transmitted from handshakes and doorknobs, etc....than from people openly sneezing).

Answer 4

Well, the flu itself changes from year to year, it evolves to become more powerful, and usually the vaccine from the previous year would no longer work. Since the flu changes, the vaccine also needs to change. However, sometimes the vaccine is even outdated during the flu season because the flu evolves, and people can still get sick even though they have the jab. Anyway thats what i think, cos some people get sick even when they had the jab.

Answer 5

Each year the influenza virus can change slightly making the vaccine used in previous years ineffective. Each year a new vaccine must be prepared that will be effective against the expected type of influenza virus. The trick is to be able to predict which influenza viruses are going to cause infection and to prepare a vaccine against those viruses. Usually scientists can predict accurately which types of influenza virus will cause infections and prepare an appropriate vaccine.

Answer 6

each year the vaccine is different because they have different strains of the flu. This year the vaccine has New Caledonia, Macedonia, and Malaysia strains included.

Answer 7

Flu viruses change constantly and become immune to the anti-virus matter. Therefore every year this needs to be to "updated" and everybody needs to get inoculated again.

Answer 8

The viruses change from year and year. So, the shots are updated. The shots only last one year, so it is wise to get one; even if there weren't any change in the viruses.