Sir.—The article by Dr Biedel in the Journal (132:678-680, 1978), "Recurrent Mumps Parotitis Following Natural Infection and Immunization," is of particular interest to pediatricians and to members of advisory committees on immunization procedures. If mumps infection can reoccur (despite a substantial rise in specific antibody levels) in children who have received mumps vaccine or who have had clinical mumps, should children be given a booster dose of mumps virus vaccine at the time of exposure or before puberty (especially boys)?
However, Zollar and Mufson1 in 1970 reported that parainfluenza type 3 virus infection can simulate clinical mumps and result also in a rise in serum antibody levels to both parainfluenza type 3 and mumps viruses. Also, as Dr Biedel has noted, other viruses have been reported as a cause of infectious parotitis.
Dr Biedel did not obtain viral cultures in his patients, and the only serum antibody studies