Field Effectiveness of Live Attenuated Measles-Containing Vaccines: A Review of Published Literature

Abstract

BACKGROUND: Information on measles vaccine effectiveness (VE) is critical to help inform policies for future global measles control goals. METHODS: We reviewed results of VE studies published during 1960-2010. RESULTS: Seventy papers with 135 VE point estimates were identified. For a single dose of vaccine administered at 9-11 months of age and ≥12 months, the median VE was 77.0% (interquartile range [IQR], 62%-91%) and 92.0% (IQR, 86%-96%), respectively. When analysis was restricted to include only point estimates for which vaccination history was verified and cases were laboratory confirmed, the median VE was 84.0% (IQR, 72.0%-95.0%) and 92.5% (IQR, 84.8%-97.0%) when vaccine was received at 9-11 and ≥12 months, respectively. Published VE vary by World Health Organization region, with generally lower estimates in countries belonging to the African and SouthEast Asian Regions. For 2 doses of measles-containing vaccine, compared with no vaccination, the median VE was 94.1% (IQR, 88.3%-98.3%). CONCLUSIONS: The VE of the first dose of measles-containing vaccine administered at 9-11 months was lower than what would be expected from serologic evaluations but was higher than expected when administered at ≥12 months. The median VE increased in a subset of articles in which classification bias was reduced through verified vaccination history and laboratory confirmation. In general, 2 doses of measles-containing vaccine provided excellent protection against measles.