In 1992, there was a setback in measles vaccination for developing countries as high-titre vaccines were withdrawn following reports of excess mortality in vaccine recipients. The importance of continuing polio vaccination in industrialized countries was emphasized by an outbreak of paralytic polio among an unimmunized community in the Netherlands. Immunization programs are now increasingly using the Jeryl Lynn strain of mumps vaccine following reports of meningoencephalitis associated with the Urabe strain. A hepatitis A vaccine has become generally available and hepatitis B vaccine is being introduced into more childhood programs in countries where the disease is highly prevalent. Trials of group B meningoccal meningitis vaccines have yielded disappointing estimates of efficacy, particularly in younger children. Earlier reports of invasive bacterial infections after pertussis immunization have not been confirmed.