Some New Mexicans will get smallpox vaccines over the next six to nine months, but how big of a threat the disease really is still remains a mystery, said Ron Voorhees, deputy state epidemiologist.

The state plans to give some nurses, epidemiologists and emergency medical providers the first vaccines over the next few months, followed by police, firefighters and other emergency personnel in later stages, Voorhees said.

Smallpox, globally eradicated 25 years ago, has come back to haunt public health authorities with the prospect that it could be used as an instrument of terrorism.

"The medical people will be the first to go in and see if a disease actually is smallpox," Voorhees said. "After that will be the other emergency personnel. The problem is, we don't know how realistic a threat smallpox is."

As many as 12,000 New Mexicans will get smallpox vaccinations over a six- to nine-month period under a plan unveiled by the state Department of Health.

The plan calls for voluntary smallpox vaccinations to begin around mid-January. It is part of a federally-led effort to inoculate frontline personnel against the disease.

The vaccine should be effective against normal forms of smallpox, but enhanced bioterror versions of the disease could be another story, Voorhees said.

"I have no idea how well they would work on a modified version of the disease," Voorhees said. "If it's virulence was modified, a vaccine might work somewhat, but if it was modified so that the vaccine wouldn't work against it, then there's no protection. We'd have to isolate people with it. That's not something we can anticipate."

In addition, one hospital, followed later by two others, will be designated to handle side effects of the vaccine, which can cause serious medical problems and even death.

So far, there are no plans to give the vaccine to the general public, Voorhees said. "That's a decision that hasn't been made yet. That depends on how likely the threat is. That would be up to the federal government, but the decision so far is not to proceed."

The last case of smallpox in the world was recorded in 1977. The last one in the United States happened in the 1940s, Voorhees said.

"What remains to be seen is how many health care workers will actually volunteer for this," Sewell said.

Most Albuquerque hospital representatives said Monday that they didn't know yet how many and which workers they would vaccinate.

The exception was the Veterans Administration Medical Center, where spokesman Michael Kleiman said the hospital is forming a core vaccination team with one or two physicians and eight or nine registered nurses. In addition, about 100 staff members will be immunized, he said.

The Associated Press contributed to this story.