A panel of U.S. scientists has concluded that while the only currently available anthrax vaccine could be improved, it is safe and effective, even against the most deadly form of the disease.

The anthrax vaccine has been extremely controversial among U.S. soldiers. Since it was not approved by regulators for the most deadly form of the disease, inhaled anthrax, military personnel resigned rather than allow themselves to be vaccinated against possible anthrax exposure in the Middle East.

A panel of the National Academy of Sciences was studying the issue last fall, when someone began sending deadly anthrax spores through the mail, resulting in the deaths of five people.

The terrorist acts gave the scientists' mission a sense of urgency,resulting in the release Wednesday of the report's findings.

Brian Strom of the National Academy of Sciences' Institute of Medicine chaired the panel. "So is the vaccine safe? Our committee concluded that it is sufficiently safe to be useful," he said. "Still, its side effects coupled with the long series of doses required are among the realities that underscore the need for a new and improved alternative."

Dr. Strom says a typical side effect is redness of the skin where the injection is given. The side effect is typical of other vaccines, such as tetanus, and presents no serious health problems.

Dr. Strom adds there may be more serious side effects, that researchers have yet to uncover, because the vaccine has not been in use for very long.

Dr. Strom called on the Department of Defense to assist in the development of a new anthrax vaccine.

"Ideally, a new and improved vaccine should not cause any severe reactions," he said. "And, among other characteristics, it should require only two or three injections, provide immunity within 30 days that lasts a year and should remain potent for a long period of time so it can be stockpiled to ensure ample supplies when needed."

Under normal circumstances, anthrax vaccine would not be needed because in most places the risk of coming in contact with the naturally occurring bacterium is minimal.