wo major hospitals announced last week that they would not participate in offering smallpox vaccinations to their health workers, and press reports suggest that several others may do the same. Such recalcitrance is perfectly legal. The federal government's smallpox vaccination program is voluntary for both hospitals and health workers. But the decision is deplorable all the same. The refusal to participate raises needless suspicions about the nation's smallpox preparations and could, if dropout fever spreads too widely, undermine efforts to prepare for bioterrorism.

The administration's program calls for smallpox vaccine to be offered soon to some 450,000 health and emergency workers and later to an additional 10 million. The states have developed plans for administering the vaccine and are counting on hospitals to participate. The program can survive a few defections, but the more hospitals that participate the better. No one can be sure where the first smallpox victims might seek treatment.

The two big hospitals that have already dropped out, in Atlanta and Richmond, Va., argue that a smallpox attack seems unlikely whereas the vaccine can cause severe and even fatal complications in a few who receive it (roughly two deaths for every million people vaccinated). There is also a slight risk that careless hospital workers might spread vaccinia virus to some of their patients, causing severe harm to those with weakened immune systems or certain skin disorders.

But there are very good reasons for hospitals to offer the vaccine on a voluntary basis. Historically, hospitals have been focal points for spreading smallpox. Typically a smallpox victim would show up for treatment and by the time doctors recognized the disease would have infected more than a dozen other patients or health workers. Vaccinating the health workers can protect not only them but their patients as well. The likelihood that the workers at any one institution would suffer life-threatening side effects is exceedingly small, and experts say the risk of spreading vaccinia virus to vulnerable patients can be readily controlled by simple protective measures. Hospitals and health care professionals are accustomed to taking risks for the greater good. They should heed the president's call to prepare for the threat of bioterrorism.