Measles Vaccines

Vaccination Recommendations

Two measles, mumps, and rubella (MMR) vaccines are licensed in the US: M-M-R _II (Merck & Co) and PRIORIX (GlaxoSmithKline Biologicals); these two vaccines are fully interchangeable in the schedule. MMR is also available in combination with varicella vaccine (MMRV; ProQuad [Merck & Co]). The measles component of these combination vaccines is a live attenuated measles morbillivirus (MeV) strain (the Moraten strain for M-M-R _II and ProQuad and the genomically identical Schwarz strain for PRIORIX). The vaccines are lyophilized for storage and distribution, and are intended for administration by subcutaneous (M-M-R _II and PRIORIX) or intramuscular (M-M-R _II only) injection immediately after reconstitution.

The efficacy of a single dose of a live attenuated measles vaccine is estimated at 77% when administered at 9-11 months of age and 92% when administered at ≥12 months of age. Two doses of the vaccine increase vaccine efficacy to 94%. Measles vaccines are generally safe and well-tolerated. For MMR vaccines, the most common adverse events (AEs), not including injection-site reactions, are fever (<15%), transient rashes (5%), transient lymphadenopathy (20% in adults and 5% in children), or parotitis (<1%). For the MMRV vaccine, the most common AEs are fever (<22%), irritability (<7%), and transient rashes (≤3%). Compared to separate MMR and varicella vaccination (MMR+V), the MMRV vaccine carries an increased risk of febrile seizures, with an estimated 2.2 seizures per 10,000 doses for MMR+V and 5.8 seizures per 10,000 doses for MMRV.

According to the CDC/ACIP, all children should be immunized against measles, with the first dose administered at 12-15 months, followed by a second dose at 4-6 years of age. Because of slightly increased risk of febrile seizures when the MMRV vaccine is administered in children 12 to 47 months of age, MMR (plus a separate vaccine for varicella) is recommended by the CDC as a first dose in this age range. The AAP considers both MMR plus VAR and MMRV acceptable, if the child’s caregivers are fully informed about the risk/benefit ratio. Given the general preference for combination vaccines, MMRV is preferred as a first dose in children 4-12 years of age, and for second doses. The routine vaccination schedule for measles immunization in pediatric patients is shown in Figure 4-1.

In certain cases, including planned international travel or an ongoing measles outbreak, children 6-11 months of age can receive a dose of MMR, but this dose does not “count” towards the routine vaccination schedule, which begins at 12 months of age. International travel and local measles epidemic also justify an acceleration of the vaccination schedule in children ≥12 months of age; the CDC/ACIP recommendation in such cases is for two measles vaccine doses administered at least 28 days (for MMR vaccines) or 3 months (for the MMRV vaccine) apart. The recommendations for routine, catch-up and vaccination in special situations are summarized in Table 4-2.

The CDC/ACIP recommends that adults born in 1957 or later who do not have evidence of immunity (Table 4-3) to measles (or mumps or rubella) should receive, at a minimum, one dose of an MMR vaccine. Because of historically high prevalence of measles, adults born before 1957 are considered to be immune to measles. Nevertheless, one or two doses (spread at least 28 days apart) of an MMR vaccine can safely be given to persons born before 1957, and vaccination with 2 doses should specifically be considered for healthcare personnel (HCP) born before 1957 (and is recommended in the case of an outbreak; see Table 4-3). Adults of all ages without evidence of immunity to measles who are considered to be at potentially increased risk of exposure to measles (a category that includes university students, persons employed in childcare or educational settings, international travelers and health care provider (HCP) should receive two doses of an MMR vaccine.

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