Adverse events following a third dose of measles, mumps, and rubella vaccine in a mumps outbreak.

During a 2009-2010 mumps outbreak in a New York State village, a third dose of measles, mumps, and rubella (MMR) vaccine was administered to children in three schools as a control measure. Information on local and systemic adverse events (AE) was collected by a self-report survey distributed to all children in grades 6-12. A comprehensive search for AE following MMR vaccination was conducted using physician records and the Vaccine Adverse Events Reporting System (VAERS). A literature search was performed for published reports pertaining to AE associated with mumps-containing vaccine, using the Jeryl-Lynn strain, from 1969 to 2011. A total of 1755 individuals received the third dose; 1597 (91.0%) returned the survey. Of those, 115 (7.2%) reported at least one local or systemic AE in the 2 weeks following vaccination. The most commonly reported AE were "pain, redness, or swelling at the injection site" (3.6%) and "joint or muscle aches" (1.8%). No serious AE were reported in the survey, physician records or through VAERS. The proportions of AE found in the present study were lower than or within the range of those reported in prior studies of first- and second-dose MMR vaccine studies. The results of this study suggest that a third dose of MMR vaccine administered in an outbreak setting is safe, with injection site reactions reported more frequently than systemic reactions. However, to assess risk for rare or serious AE after a third dose of MMR vaccine, longer term studies would be required.