Comparative study and evaluation of further attenuated, live measles vaccines alone and in combination with mumps and rubella vaccines.

The further attenuated Enders (FAE) measles vaccine strain and the Edmonston B-Zagreb (EZ) measles vaccine strain were compared. In VERO-cells plaque sizes of FAE varied between 0.5 and 1 mm, those of EZ between 1 and 2 mm in diameter. The lots available in Switzerland during a 2 year period showed virus titers of 10(3.1) to 10(4.0) TCID50 per dose in the one vaccine (FAE) and of 10(3.1) to 10(4.5) TCID50 per dose in the other (EZ). Clinical investigations were performed with FAE and EZ monovalent and trivalent (measles + mumps + rubella) vaccine preparations. The virus titers of the vaccine lots used were 10(3.1) to 10(4.0) TCID50 per dose. The overall seroconversion rates of 96% to 100% indicate that both types of vaccine have comparable immunization properties. Stability tests demonstrated good stability of both the FAE and the EZ vaccines. Thus conservation at 37 degrees C was possible for 2 and 4 weeks, respectively, and at 41 degrees C for 6 and 6 days, respectively, without undue loss of live virus content (less than 1 log 10). Since the EZ vaccine is derived from human diploid cells, it is particularly suitable for the vaccination of persons with a history of allergy to avian proteins.