Whether many Maine hospitals will volunteer to create smallpox response teams remains unclear as they contemplate serious unknowns and risks related to the vaccinations of doctors, nurses and other medical workers.

Late last week, Maine’s Bureau of Health sent a detailed four-page letter to hospital administrators and infection control officers describing the apparent health and liability risks.

“There are a lot of issues for them to grapple with,” said Dr. Dora Anne Mills, director of the bureau.

Under the state plan created at the behest of the Bush administration, 100 medical workers are supposed to be vaccinated next month. Those same medical workers will help vaccinate at three facilities the hospital teams that would be available to treat smallpox victims.

A key concern for hospitals is that they may not be protected against medical and liability claims from employees and nonemployees who suffer possible side effects from the vaccine.

The Homeland Security Act protects the state and federal governments, the vaccine manufacturer and the facilities where vaccinations are administered from lawsuits. But it doesn’t provide indemnification for hospitals whose employees volunteer for vaccination, according to the Centers for Disease Control and Prevention in Atlanta.

The CDC’s interpretation surprised the American Hospital Association, which thought hospitals would be protected when the law was passed, said Sandra Parker, counsel for the Maine Hospital Association.

Now, “the concern is if somebody gets sick, who will pay for the care of that patient,” she said. She said colleagues around the country are grappling with the same issues.

The problem is that health insurance may not pay for an illness stemming from a vaccination taken for work reasons.

And workers’ compensation might not cover an illness either, since the vaccine was taken voluntarily. The state’s Workers’ Compensation Board is talking about this internally, Parker said.

Then there is the risk, though small, that employees who didn’t volunteer, or even nonemployees who are close to a volunteer, could become ill from coming in contact with the vaccinia virus, a mild form of smallpox used in the vaccine. Hospital liability insurance might not cover that, Parker said.

Back when smallpox vaccination was the norm three decades ago, about 1,000 of every million people vaccinated had reactions requiring medical attention. About 14 or 15 out of a million people vaccinated experienced life-threatening reactions and about one or two in a million died.

But this data may not be a good present-day indicator. Today there are more diseases compromising the immune system and new drugs on the market with unknown interactions with the vaccine, experts say. There have even been questions about whether mutations would render the old vaccine ineffective against smallpox, Parker said.

Smallpox vaccine was the world’s first vaccine. In fact, “vaccination” is a derivation of “vaccinia,” the form of smallpox used to immunize individuals against the full-blown disease.

Although the success of vaccination allowed the World Health Organization to declare the world free of smallpox in 1980, the virus lives on in laboratories. The concern is that terrorists might use smallpox as a weapon.

As the unknowns and liability issues are considered further in relation to response teams, the state’s hospitals are taking care before deciding whether to participate, Parker said.

Eastern Maine Medical Center, Maine’s second-largest hospital, is focusing on the safety of the staff, said spokeswoman Jill McDonald. She said the Bangor hospital’s emergency preparedness team and other medical workers are trying to balance the desire “to support our country in what is essentially a war effort,” with concerns about putting employees in harm’s way.

“That’s not something these folks are going to take lightly,” McDonald said.

Officials at Bangor’s smaller general hospital, St. Joseph Hospital, declined to discuss deliberations. Spokeswoman Diane Galutia said no decisions had been made pending another meeting with state health officials.

Hospitals will have still other issues to consider in deciding whether to create response teams. Volunteers must be screened for conditions that would exempt them from consideration.

Those cleared for participation will need to travel to one of three vaccination sites in the state. For the trip and a follow-up visit, hospitals will have to consider providing paid time off. The volunteers also will need to attend an eight-hour training session on smallpox and the care of smallpox victims.