Inactivated measles virus vaccine. Subsequent challenge with attenuated live virus vaccine.

Abstract

Formalin-killed, aluminum-adsorbed vaccine given in three monthly doses uniformly gave immunity to persons susceptible to measles; two doses produced immunity in all but one, and a single dose in approximately 67% of those susceptible. When challenged with live virus vaccine, children who had had two or three doses of killed virus (KV) vaccine responded with a sharp rise in neutralizing antibodies without becoming ill. Of those who had had one dose, sharp increase in neutralizing antibodies (NA) developed in all but one, and febrile reaction and rash were reduced to a minimum. Regimens of one, two, or three doses of killed vaccine followed a month later by challenge with live virus (LV) are effective alternatives to the use of live virus vaccine alone and eliminate most of the febrile reactions and rashes caused by live virus vaccine, without sacrificing the immunizing effect.