In a study of MMR seropositive volunteers who received a booster shot (similar to our subject), low frequencies of virus-specific ASCs were found 1 week postvaccination; the median number of virus-specific ASCs per 106 PBMCs were just 0.38 for mumps, 0.125 for measles, and 2.25 for rubella (Latner et al. 2011). This evidence concerns the gene MRC1 and mumps infectious disease.