Mump outbreaks in young adults who were previously vaccinated pose questions about decreased tolerance to vaccines. This research established, defined and evaluated the changing occurrence of non-mumps outbreak outbreak mumps after mumps-containing (MMR/MMRV) vaccinations. Possible cases were found among members of the Kaiser Permanente Northern California between 1996 and 2018 by international classification of illness codes or by testing mumps. The medical diagrams, the pacing and the clinical features were examined to validate diagnosis. 257 of the 474 probable cases were confirmed during the analysis of the table. A third of the cases were less than 10 years old and 48% were over 25 years old. Parotitis in most patients, and orchitis in 5 percent of men. With time, the second MMR / MMRV dosage has risen from <2 year to <10 year, Mumps has fallen from 8.5 to 1.8 million people-years.

Likewise, after at least 1 dose of MMR/MMRV, rates have decreased from 16.3 to 3/1,000,000 people-years. In comparison to older groups, the rate of mumps was higher for children aged ten years. In conclusion, this research indicates that decreasing immunity from vaccines to mumps seemed to have minimal clinical effects in the form of a non-outbreak.