Why are cases being reported in people with 2 MMRs?
As of 3-23-06 the state has 187 confirmed and probable cases of mumps. Seventy-nine percent have a history of one or two MMR vaccinations. The MMR vaccine has a clinical efficacy estimated to be 95 percent after one dose. The second dose is given to catch the 5 percent who do not respond to the first dose. The vaccine does cover the strain we are seeing in Iowa. We have no evidence to suggest there is waning of the vaccine. The occurrence of serologically or virologically confirmed mumps cases in vaccinated people is predictable, as with any vaccine of less than 100 percent efficacy. This problem becomes more prominent as vaccination coverage increases. Although the overall rate of susceptibility decreases, the proportion of previously vaccinated people increases among the remaining susceptibles, and hence cases occur among vaccinated people even when vaccine efficacy is high. << Mumps information page What are other health departments doing? It is important to consider the immune stat
