A scientific panel yesterday said smallpox vaccinations carry real risks and the government should move cautiously with its plan to vaccinate health care and emergency workers beginning next week.

     In a report released yesterday, the committee recommended the White House analyze the results of the first round of immunizations before continuing the program, and said volunteer recipients should be informed they are likely to receive only minimal compensation if they are injured.
     The report was issued exactly seven days before the first of an estimated 500,000 U.S. health care workers and members of smallpox emergency response teams are to be vaccinated under a plan announced last month by President Bush.
     About 30 percent of the U.S.. population would have "contra-indications," or adverse reactions, to the smallpox vaccine, which uses a live, rather than a killed, virus, according to the report.
     "Those are the best available data and that's a high proportion," said Dr. Brian L. Strom of the University of Pennsylvania School of Medicine, who chairs the Institute of Medicine committee.
     Jerry Hauer, assistant secretary for public health preparedness with the U.S. Department of Health and Mental Hygiene, said the report sounds "relatively uninformed." He has not read it.
     "There is no reason to delay implementation of the vaccination program," Mr. Hauer said. "Many people have asked for the vaccine, and the process is being done very methodically.
     The committee said participants must understand they are not taking the vaccine to simply protect themselves but to help to prepare for a bioterrorism strike.
     "People who take [the smallpox vaccine] are taking it for the public good. They're not taking it for their personal benefit," said Dr. Strom.
     Two of the nation's largest unions representing health care workers — the Service Employees International and the American Federation of State, County and Municipal Employees — believe the vaccination program should be delayed until safety and compensation issues are resolved.
     Congress acted to protect people and institutions delivering the vaccine from most lawsuits that could be filed by those injured by the inoculation, leaving such patients with little recourse. Under the policy, injured people may have access to state workers' compensation programs, but those programs are not likely to cover all medical expenses.