The Pentagon (search) has received less than one-third of the vaccine it needs, but officials say they are working on a deal for more doses and pledge that all U.S. troops abroad, plus those preparing to go overseas, will get flu shots this fall.

Flu shots usually are mandatory for troops, as a matter of Pentagon policy, but not for the thousands of military dependents and military retirees who are entitled to Pentagon health benefits.

Immunization of troops abroad, particularly those in war zones like Iraq (search) and Afghanistan or potential areas of conflict like Korea, is a high priority because the soldiers' loss to illness would hurt military readiness.

Normally all troops are required to get vaccinated. Those not deployed abroad, however, are a lower priority, so few of them will get flu shots this year, Pentagon officials said Wednesday.

Before Chiron Corp., the Defense Department's (search) main flu vaccine supplier, cut off shipments due to safety concerns, the Pentagon had planned to use 3.7 million doses this flu season.

Earlier this month it reduced that to 2.2 million, and it said Wednesday it expects to achieve that goal.

So far it has received 680,000 doses from its secondary supplier, Aventis Pasteur, which is scheduled to ship another 620,000 doses by the end of November, a Pentagon statement said.

That would still leave the Pentagon about 900,000 doses short of its goal, but it is working on an agreement with Aventis to close that gap.

The Pentagon also is pursuing a contract with the makers of the nasal vaccine FluMist as a backup plan.

"We believe that we're well positioned to fully take care of and respond to the flu vaccination needs of the people who need the vaccine," Dr. William Winkenwerder, the assistant secretary of defense for health affairs, said in an interview Wednesday.

He declined to elaborate, saying that later this week the Pentagon plans to announce a plan for flu vaccine distribution.

The Pentagon follows guidelines of the Centers for Disease Control and Prevention in determining which groups are most at risk. Aside from troops, the Pentagon's top priority groups for immunization include military dependents age 6 months to 23 months and military retirees and dependents age 65 and older, as well as all women who will be pregnant during the flu season.

Troops who are not deployed abroad and not performing "critical operational" duties in the United States will not be vaccinated, the Pentagon said.

Of the 680,000 doses of vaccine received so far, about 480,000 doses have been delivered to the military services, mostly for U.S. troops in South Korea and the Central Command region, which includes Afghanistan, Iraq, Kuwait and Qatar.