Are Boosters Necessary If Adult Patients Do Not Achieve Seroconversion After 2 Doses of the MMR Vaccine?

The Centers for Disease Control (CDC) recommend 2 documented doses of the MMR (measles-mumps-rubella) vaccine for adequate measles, mumps, and rubella immunity for all children and most adults. Sometimes, individuals are asked to provide serologic proof of immunity to measles, mumps, and/or rubella for educational or employment purposes. In other instances, serologic testing may be used to help clarify whether an individual has immunity to measles, mumps, and/or rubella. These serologic tests may sometimes show negative or equivocal antibody titers to measles, mumps and/or rubella, raising the question of adequate immunity. This report provides practical guidance for clinicians on when to use serologic testing to determine measles, mumps, and rubella immunity.