Chicago ? Government scientists reported Monday they have created a vaccine against the catastrophic Spanish flu virus of 1918-1919, raising hopes that a remedy could be developed if a modern strain of avian flu turns equally deadly.

The Spanish flu, which infected a third of the world’s population and caused as many as 100 million deaths worldwide, is unlikely to resurface. But interest in the epidemic has been revived over the last decade as experts gird for battle against an emerging bird flu they fear could mutate into a form able to pass from human to human.

Decoding the genes of a flu virus and developing a vaccine is now a matter of months, not years, said the lead researcher of the new report, Dr. Gary Nabel, director of the National Institute of Allergy and Infectious Diseases’ Vaccine Research Center.

The study, published in the Proceedings of the National Academy of Sciences, “offers hope that conventional vaccination strategies will be an effective approach to a new pandemic influenza,” said David Topham, an influenza immunologist at the University of Rochester Medical Center in New York who was not involved in the study.

No influenza virus has been nearly as virulent as the Spanish flu. In fact, many scientists of the time questioned whether such an explosively fatal disease could be influenza at all.

Later researchers hypothesized there was something about the virus that protected it from the actions of the immune system. If that was true, vaccines would not be effective against it.

Now, working with mice, scientists have shown that a vaccine can prompt the body’s natural defenses to mount an attack on the virus – and that bodes well for future efforts to fight dangerous flu strains.

“The good news is that it’s a bad virus but it’s not resistant to vaccination,” Nabel said.

The 1918 epidemic killed 675,000 people in this country. The deadliest plague in human history, it was memorialized in literature – especially Katherine Anne Porter’s “Pale Horse, Pale Rider.”

Its cause remains a mystery, though recent research suggests the strain may have started out as a bird flu before making genetic leaps that enabled it to infect humans.