Experience with preparation an laboratory control of oral poliomyelitis vaccine in Czechoslovakia.

Among the many problems connected with the preparation and laboratory control of oral poliomyelitis vaccines, one of the most vexed is that of the presence of undesirable, extraneous viruses of simian origin, particularly the foamy viruses. In Czechoslovakia, as elsewhere, these have been encountered in the production of live poliomyelitis vaccine from Sabin strains. Of 596 single lots of primary monkey kidney cell cultures intended for use in vaccine, only 143 lots successfully passed laboratory control tests, mainly because foamy viruses were found. Comparison tests showed that monkey and rabbit kidney cells were equally sensitive for the detection of foamy viruses but that dog kidney cells were less so and, in addition, in 8% of cases contained endogenous cytopathogenic virus agents. The presence of vacuolating agent was not tested for in the control tests discussed in this paper.All vaccine lots which passed control tests and were administered to children in the course of mass vaccination campaigns in Czechoslovakia in 1960 and 1961 proved safe and effective.