In Elimination Settings, Measles Antibodies Wane Following Vaccination but Not Following Infection - A Systematic Review and Meta-Analysis.

BACKGROUND We conducted a systematic review to assess whether measles humoral immunity wanes in previously infected or vaccinated populations in measles elimination settings. METHODS After screening 16,822 citations, we identified nine articles from populations exposed to wild-type measles and 16 articles from vaccinated populations that met our inclusion criteria. RESULTS Using linear regression, we found that geometric mean titers (GMTs) decreased significantly in individuals who received two doses of measles-containing vaccine (MCV) by 121.8 mIU/mL (95% CI -212.4, -31.1) per year since vaccination over one to five years, 53.7 mIU/mL (95% CI -95.3, -12.2) five to ten years, 33.2 mIU/mL (95% CI -62.6, -3.9) ten to 15 years, and 24.1 mIU/mL (95% CI -51.5,3.3) 15 to 20 years since vaccination. Decreases in GMT over time were not significant after one dose of MCV or after infection. Decreases in the proportion of seropositive individuals over time were not significant after one or two doses of MCV, or after infection. CONCLUSIONS Measles antibody waning in vaccinated populations should be considered in planning for measles elimination.