When are titers for mumps, measles, and rubella indicated?

• A. After every dose
• B. Only if vaccine quality or storage is in doubt
• C. For all children with unknown vaccination status
• D. Never

Answer: (B)

Titers for mumps, measles, and rubella are not checked routinely after vaccination. They’re best used only when there’s a real reason to doubt whether the vaccine actually delivered protective immunity—most notably if the vaccine’s quality or cold-chain storage could have been compromised. In that scenario, measuring antibodies helps decide whether someone is protected or if another dose is needed. If there’s no concern about the vaccine’s potency and there’s no documented immunity, re-vaccination is the standard approach rather than ordering a titer. That’s why this question’s correct choice is to test only when vaccine quality or storage is in doubt.