Menstrual and ovulatory disturbance in bulimia.

probably reflects increases in urban violence and the number of drug abusers. Nevertheless, few officers had markers of hepatitis, which suggests that unreported exposure is uncommon. A central service for the Metropolitan Police Force seems to work well; police officers and surgeons generally know the correct course of action after exposure, and prophylaxis can be given when it is most likely to be effective. An increasing problem is unavailability of blood from contacts, particularly drug abusers, who are often uncooperative and may have sclerosed veins; this may result in costly hepatitis B immunoglobulin being given unnecessarily. Vaccination ofpolice officers would be effective in reducing the risk of acquiring hepatitis B but would be expensive; at £32.60 per course it would cost over £880 000 to vaccinate the 27 000 officers in the Metropolitan police alone. The group most at risk is officers on ordinary street duty, some of whom have already been vaccinated by their general practitioners. Most officers can avoid contamination with hepatitis B by adopting precautions such as taking care with needles and wearing gloves when dealing with bleeding accident victims. For the others a service such as ours seems the most cost effective in preventing hepatitis B.