Simian cytomegalovirus and contamination of oral poliovirus vaccines.

In the 1950s the use of primary rhesus macaque kidney cultures to propagate poliovirus for vaccine production led to the contamination of vaccines with simian virus 40 (SV40). African green monkey kidney (AGMK) cultures free of SV40 were used as an alternative cell substrate for vaccine manufacture. In this study we evaluate oral poliovirus seeds, vaccine bulks and vaccines themselves for the presence of a common contaminant of AGMK cultures, simian cytomegalovirus (SCMV). Using sensitive polymerase chain reaction (PCR) techniques, nearly half of the samples analysed were found to be contaminated with SCMV sequences. However, vaccine bulks, positive by PCR for SCMV failed to show any evidence of infectious virus in these studies. One poliovirus vaccine and one seed, propagated on rhesus macaque kidney cultures were found to be positive for the rhesus monkey CMV by PCR.