Live Attenuated Mumps Virus Vaccine. 1. Vaccine Development

Abstract

The development and testing of an attenuated live mumps virus vaccine designated Jeryl Lynn strain, level B, is described. The virus was attenuated by passage in embryonated hens' eggs and in cell cultures of chick embryo and the vaccine was tested for safety and potency by procedures consistent with contemporary standards for live measles virus vaccine. The vaccine was used as a dried product and was sufficiently stable both in dried form and on rehydration to permit use in routine practice. It was possible to distinguish the attenuated virus from a “virulent” mumps virus strain based on cyto-pathic effect and on titer obtained in tests in primary human amnion and in chick embryo cell cultures but not in cultures of monkey kidney or HeLa or stable human amnion (WISH). It was not possible to distinguish the level B Jeryl Lynn virus from less attenuated level A virus in cell culture but the level B virus did induce considerably less antibody in monkeys than did level A. Both the level A and level B vaccines were highly immuno-genic for man. A review was made of additional data published elsewhere in which it was shown that the B level vaccine was highly efficacious in preventing natural mumps and that the virus was neither excreted from vaccinated persons nor was it contagious to susceptible contacts. All of 10 lots of human immune globulin of diverse source tested contained mumps neutralizing antibody in the range of titer of 1:64 to 1:2048 with a median of 1:256.