Differentiation of vaccine and wild mumps viruses using the polymerase chain reaction and dideoxynucleotide sequencing.

Parts of the F gene from 16 mumps viruses derived from vaccines and clinical isolates were amplified using the polymerase chain reaction and their nucleotide sequences were determined. Over a region of 111 nucleotides, eight regions of variability were detected with a maximum of six (5.4%) changes occurring between any two virus strains. The Jeryl Lynn and Urabe vaccine strains were clearly different from each other and from wild virus isolated from cases of non-vaccine-associated mumps. In contrast, viruses isolated from the cerebrospinal fluid and throat in cases of meningitis and parotitis following vaccination with the Urabe strain were identical to this strain. We conclude that the vaccine was the source of these infections.