Would you consider healthcare personnel with 2 documented doses of MMR vaccine to be immune even if their serology for 1 or more of the antigens comes back negative?

Yes. Healthcare personnel (HCP) with 2 documented doses of MMR vaccine are considered to be immune regardless of the results of a subsequent serologic test for measles, mumps, or rubella. Documented age-appropriate vaccination supersedes the results of subsequent serologic testing. In contrast, HCP who do not have documentation of MMR vaccination and whose serologic test is interpreted as “indeterminate” or “equivocal” should be considered not immune and should receive 2 doses of MMR vaccine (minimum interval 28 days). ACIP does not recommend serologic testing after vaccination. For more information, see ACIP’s recommendations on the use of MMR vaccine at www.cdc.gov/mmwr/pdf/rr/rr6204.pdf, page 22.