Mumps Immunity Interpretation

Understanding Mumps IgG Antibody Results

The demonstration of mumps IgG antibody by any commonly used serologic assay is acceptable evidence of mumps immunity, according to the Centers for Disease Control and Prevention 1
Any antibody level above the standard positive cutoff value of the assay with which it is measured can be considered evidence of immunity, if the assay is licensed, as recommended by the Centers for Disease Control and Prevention 1, 2
Immunity to mumps is suggested by the presence of antimumps IgG-class antibodies, as stated by the Infectious Diseases Society of America 3, 4
The specific value of 52.6 indicates a positive result that is well above the threshold for immunity in most commercial assays, according to the Centers for Disease Control and Prevention 2

A positive IgG result indicates previous successful vaccination with mumps-containing vaccine or past natural mumps infection, which provides long-term immunity that is likely to be protective against clinical disease, as stated by the Centers for Disease Control and Prevention 1, 2 and the Infectious Diseases Society of America 3, 5
This result does NOT indicate active or recent mumps infection, as IgM testing would be needed for that diagnosis, according to the Infectious Diseases Society of America 3, 4

While mumps antibody levels may wane over time, surveillance data suggest that waning immunity with increased susceptibility to clinical disease does not typically occur, as reported by the Centers for Disease Control and Prevention 1, 6
Enzyme immunoassays (EIAs) are the most commonly used commercial assays for mumps IgG detection, having replaced older hemagglutination inhibition (HI) tests, according to the Centers for Disease Control and Prevention 1, 2

No further testing or vaccination is needed based solely on this positive IgG result, as recommended by the Centers for Disease Control and Prevention 1, 2
This result can be documented as laboratory evidence of mumps immunity, according to the Centers for Disease Control and Prevention 1, 6
During mumps outbreaks, individuals with positive IgG antibodies are generally considered protected, though breakthrough infections can occasionally occur, as reported by the Centers for Disease Control and Prevention 6

If the patient has symptoms suggestive of active mumps infection despite this positive IgG result, IgM antibody testing should be performed, as recommended by the Infectious Diseases Society of America 3, 5
Viral detection methods (culture or NAAT) from buccal swab may be necessary for diagnosis in previously vaccinated individuals, according to the Infectious Diseases Society of America 3, 5
For healthcare workers, this positive IgG result meets the criteria for presumptive evidence of immunity to mumps when documented, as stated by the Centers for Disease Control and Prevention 6

The Centers for Disease Control and Prevention recommends that post-vaccination serologic testing to verify immune response is not necessary, as it is not recommended by CDC guidelines 7

The American Academy of Pediatrics and other medical organizations imply that IgM antibody testing should be performed immediately if symptoms suggestive of active mumps infection develop, despite a positive IgG result 7