The type of vaccine used depends on a person's age.

Since 1996, a new vaccine that causes fewer side effects has been used.

Are you saying that the vaccine could be used safely?

An Army spokesman said the vaccine is being used in tests involving 500 people at 17 places.

Such vaccines cannot be used on patients with a weakened immune system.

But now scientists and Federal regulators are asking whether the vaccine should be used at all in healthy children.

Contraceptive drugs and vaccines have been used for a few species.

And this time, federal officials said, the vaccine won't be used until there are signs a pandemic is under way.

This vaccine is not usually used in children over the age of 5 or in adults.

It looks like the vaccine can also be used to treat certain forms of bladder cancer.