Distribution of neutralizing measles antibodies serum concentration according to age in women of childbearing age in France in 2005-2006

Measles-vaccine coverage (MVC) increased significantly only beginning in 1983 based on the official recommendations. The majority of women born after 1983 should have vaccine-acquired rather than naturally derived immunity. Passively transferred measles antibodies (Mab) are expected to provide protection to offsprings during their 1st few months of life. Objective. Compare neutralizing Mab titers according to age in women aged 12-40 years, i.e., born before and after 1983. Methods. A multicenter seroepidemiological study was conducted in France in 2005-2006; 2.1.0 outpatient or hospitalized women were enrolled and classified into 4 age groups (12-18, 19-22, 23-30, and 31-40 years). Mab titers were assessed using a reference plaque reduction neutralization assay (protection threshold > 120 mIU/ml). Results. Ninety-four percent of subjects had a Mabs titer greater than 1.20 mlU/ml. Women born before 1983 had significantly higher geometric mean titers (GMTs) of Mabs than those born after 1,983 (1,358 mIU/ml vs. 731 mIU/ml [p < 0.001]). The comparison of the 4 cohorts showed a significant decrease) < 0.001) in GMTs of Mal) in the female population with increasing age (670, 771, 1173, and 1821 mUI/ml, respectively, in the 12-18, 19-22, 23-30, and 31-40 years age groups). For the 1st time in France, we show in women of childbearing age that in 2005-2006 neutralizing Mab GMTs were far above protective threshold for all age groups. Women in younger age groups (with high MVC) have significantly lower Mab titers. A lower passive transfer of Mab to their offsprings could result in a shorter period of measles protection and question the measles vaccine 1st dose at 1 year. (C) 2008 Elsevier Masson SAS. All rights reserved.