11.   Still, regular summer vacationers to tick-prone areas and people who make long-term plans should consider taking the vaccine.

12.   The less painful form of administration also could lead more healthy adults and children to take flu vaccines, Aviron said.

13.   The National Guard in Fort Wayne has refused to take the vaccine.

14.   The Pentagon said it does not track the number of people who have left the military for refusal to take the vaccine.

15.   The people taking the vaccine must sign forms acknowledging that the medicine is not licensed and is being administered in an exploratory fashion.

16.   The Pentagon has dismissed such concerns and has sought court-martials of soldiers who refused to take the vaccine.

17.   The updated vaccine should be taken each fall before the start of the new flu season, which usually occurs from November through April.

18.   The volunteers will take a vaccine that has been controversial.

19.   They give blood, take experimental vaccines and ingest suspect bacteria, and when they become sick they are treated on the spot.

20.   They cannot be members of the military, who may already have been vaccinated or may be required by the Pentagon to take the vaccine in the future.