Studies with Live Attenuated Measles-Virus Vaccine

The significant antigenic and protective effects of live attenuated measles-virus vaccine have been well documented.¹⁻¹⁶The immunologic response in children without initial measles antibodies has exceeded 95%.⁹The prophylactic effect has been observed in institutional epidemics⁶,¹³2, 10, and 15 months after immunization. All vaccinees were solidly protected under conditions which induced a 58% to 90% attack rate of measles in unvaccinated controls. In addition, intimately exposed household contacts have resisted infection after successful vaccination with live attenuated measles vaccine. Clinical reactions to the vaccine have been limited chiefly to fever and rash. Respiratory symptoms have been minimal or absent. Among 171 susceptible children, a detectable febrile response has been reported in approximately 83% and an exanthem in 48%.9 At least 30% of susceptible vaccinees have exhibited temperature elevations exceeding 103 F. These significant febrile reactions, unless modified, would obviously limit the usefulness of this highly effective