Marshall County Health Department provides clarification regarding MMR vaccination recommendations in adults.
Background: Most adults in the U.S. are at low risk for measles.
- From January 1 to May 3, 2019, 764 cases were reported to CDC. Of these, 195 (26%) measles cases were reported in adults ≥18years of age. 70% of adult cases were associated with close-knit communities and 46% of adult cases were reported in NY (NNDSS)
- From 2001-2015, the reported incidence for adults ≥18 years of age was <0.5/1,000,000, whereas the risk for children aged 6 to 11 months was 5.44/1,000,000 and children aged 12 to 15 months was 5.38/1,000,000 (Clemmons, et al, JAMA 2017)
- Seroprevalence of measles IgG in the U.S. for persons 20-49 years of age ranges from 87.9% to 93.3% (Lebo et al., OFID 2017)
Recommendations: One dose of MMR vaccine, or other presumptive immunity, is sufficient for most U.S. adults born on or after 1957.
Other presumptive evidence of measles immunity includes:
- Birth before 1957
- Laboratory evidence of immunity
- Laboratory confirmation of disease
Certain adults are considered to be high risk and need two doses of MMR, each dose separated by at least 28 days, unless they have other presumptive evidence of measles immunity, as listed above. These adults include:
- students at post-high school education institutions
- healthcare personnel
- international travelers
Some adults may have received a killed measles vaccine during the 1960’s. The killed measles vaccine was available from 1963 to 1968 and administered to less than 5% of adults. The ACIP recommendation is to re-vaccinate anyone who received the killed vaccine. However, this only affects a very small proportion of adults that were vaccinated during those years.
During outbreaks, health departments may provide additional recommendations to protect their communities. The at-risk population is defined by local and state health departments, depending on the epidemiology of the outbreak. Thus, if the outbreak is affecting preschool-aged children or adults with community-wide transmission, a second dose should be considered for children aged 1 through 4 years or adults who have received 1 dose. In addition, during measles outbreaks involving infants aged <12 months with ongoing risk for exposure, infants aged ≥6 months can be vaccinated. CDC is working on clinical guidance for protection of infant travelers to areas within the United States that are experiencing sustained measles transmission.
Clarification of recommendations:
- There is no recommendation for an adult catch-up program for persons born before 1989
- There is no recommendation for vaccination campaigns among adults or individuals in non-affected areas to prevent measles outbreaks