WASHINGTON (AP) -- Doctors don't know yet if it will take one dose or two of vaccine to protect against the new swine flu. Add that to vaccine for the regular winter flu, and it could be a multishot season for a lot of people -- or a multisquirt season, for those who choose the FluMist nasal-spray version.

Some possibilities:

-- One shot: Older adults currently aren't on the priority list to get swine flu vaccine but they should get the seasonal vaccine, which is available.

-- Two shots: There's a potential for the regular vaccine in one arm and the swine flu vaccine in the other, if that one requires just one dose.

-- Three shots: The swine flu vaccine might require two doses three weeks apart, plus the regular vaccine.

-- Four shots: There's even this possibility for some children. Youngsters under 9 who are getting their first-ever regular flu vaccination need two doses of it.

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