Last Updated: 2002-12-20 10:00:34 -0400 (Reuters Health)

WASHINGTON (Reuters Health) - Federal officials on Thursday revealed how they propose to vaccinate Americans against smallpox, noting that it is a high-stakes challenge that puts the public's health and the public health system's credibility at risk.

The first vaccinations of health workers could start as soon as January 24, Centers for Disease Control and Prevention (CDC) officials told an Institute of Medicine (IOM) panel that has been asked to help put the plan in place. About 100 military doctors and nurses received smallpox injections on Wednesday.

The CDC officials urged the IOM members to give their advice by mid-January if possible. The government aims to vaccinate healthcare workers within 30 days of starting.

The Bush administration announced December 13 that military personnel and health workers will be immunized first, followed by "first responders," such as police and fire officials. The vaccine would be made available to the general public later next year.

The CDC is evaluating vaccination plans from 50 states and four major cities, and has accepted half, said Raymond Strikas, of the agency's smallpox preparedness office. More than 430,000 people, out of a target 500,000, have been identified as candidates for vaccination, he said.

IOM panelists asked why the plan was being rolled out so fast. Walter Orenstein, director of CDC's National Immunization Program, said the agency "has been asked to do this as expeditiously as possible," but that it also wants to do it safely.

Some committee members said they worried that politics are taking precedence over safety, noting that they have been given no information on the risk of a smallpox attack.

The vaccine has some rare, but potentially fatal side effects, and those immunized also risk infecting themselves or others with the live vaccinia virus used in the shot. The elderly, pregnant women, children, those with skin conditions like eczema, and the immunocompromised are especially at risk from vaccinia virus.

The American Nurses Association said it "is particularly concerned about the potential transmission of vaccinia virus to patients and family members." The ANA also said that nurses should be compensated for days missed due to side effects, and that none should be penalized for refusing the vaccine.

Strikas assured the panel that anyone could refuse vaccine, and that the CDC is working to ensure no one is inappropriately vaccinated.

Potential vaccinees will receive information on the vaccine and side effects and be advised to be tested for pregnancy, AIDS, and other contraindicated conditions, and to determine if household members have any of those conditions.

They could refuse vaccination or return for a shot. Clinic workers will still ask detailed questions before immunizing anyone, said the CDC's Lisa Rotz. The advice to clinics will be: "When in doubt, defer," she said.

Data on initial vaccinees will be collected and used to help calculate risk to the general public.

The US military began its vaccination program December 13. Out of 276 people screened, 102 or 37% opted out because of contraindications, said William Winkenwerder, an assistant secretary of defense.

In January, the military will expand vaccination to 25,000 key medical workers, and later in the month, to 500,000 troops.

Israeli experience so far suggests no unexpected side effects, said Yehuda Danon of Tel Aviv University.

One third of the 17,500 healthcare workers and first responders vaccinated have had fatigue and weakness, and smaller numbers of other symptoms like nausea, headaches, and fever. There have been only two cases of contact vaccinia, one serious, he said.