The new hepatitis B vaccine is an effective method of preventing hepatitis B infection. However, its expense could contribute greatly to health care costs, with little marginal benefit if it is used indiscriminately. This study analyzes the relative risk of hepatitis among various health care workers to determine the relative merits of a vaccine strategy. It was found that the average cost of a hepatitis B vaccine in health care facilities is greatly reduced the closer the worker is to a dialysis unit. This might justify not using the vaccine at all in health care workers at facilities without dialysis. Analyzing the marginal cost of immune serum globulin (ISG) versus hepatitis B immune globulin (HBIG) and hepatitis B vaccine in a needle-stick protocol, it was determined that the increased protection provided by HBIG and hepatitis B vaccine comes at a cost that would be considered prohibitive by many prudent decision-makers. A separate analysis of the use of hepatitis B vaccine versus ISG in troops assigned to Korea found that most decision-makers might think the cost of hepatitis B vaccine prohibitive, with the benefits mostly speculative and unproved. Data are not available that would allow a benefit-cost analysis of hepatitis B vaccine in most dental personnel.(ABSTRACT TRUNCATED AT 250 WORDS)