Measles-specific Neutralizing Antibodies in Rural Mozambique: Seroprevalence and Presence in Breast Milk

Abstract

Abstract. In Mozambique, as in many sub-Saharan countries, measles remains a public health problem. We conducted cross-sectional surveys in which we assessed measles-specific antibodies in serum and breast milk by plaque reduction neutralization (PRN) assay and measles secretory IgA in breast milk by enzyme-linked immunosorbent assay. A total of 151 persons < 1 month to 23 years of age were surveyed; 81 (53.6%) of 151 had PRN titers equal to or above the protective level (Ն 200 mIU/mL). We found many serosusceptible persons, including 20.5% in whom no PRN antibody was detected. Almost all (96%) infants 6-8 months of age had non-protective PRN titers. Overall, 20.7% (6 of 29) of persons known to have received measles vaccine had non-protective titers. The geometric mean titer (GMT) of breast milk PRN antibodies was 41.6 mIU/mL (95% confidence interval [CI] ‫ס‬ 34.0-51.0 mIU/mL) and the secretory IgA GMT was 227.6 (EU/mL) (95% CI ‫ס‬ 179.1-289.1 EU/mL). The PRN titers of breast milk tended to increase with age. A notable proportion of the population in Manhiça, Mozambique apparently remains susceptible to clinical measles despite recent mass vaccination campaigns.

Long Antibody Persistence and Transgenerational Transfer of Immunity in a Long-Lived Vertebrate

“…Reexposure of women to a vaccine or natural antigen can consolidate their immunity, although it does not augment the titer of antibodies in the long term (Leuridan et al 2010), a finding similar to our result in Cory's shearwater with the NDV vaccine. The transfer of colostrum and milk after birth nevertheless allows the persistence of significant levels of specific antibodies for several months after birth in humans (Mandomando et al 2008;Leuridan et al 2010). Our results thus highlight the need for further comparative approaches exploring relationships between life-history traits, patterns of exposure to infectious diseases, and characteristics of transgenerational immunity.…”

A 16-year review of seroprevalence studies on measles and rubella

“…Several other specimen types were used including breast milk [34], oral fluid [38,70] and blood derived from the umbilical cord, earlobe or finger prick [61,79] and umbilical cord serum [31].…”

“…Overall, the seroprevalence of measles ranged from 53.6% in a population study in Mozambique [34] to 99.0% in an infant study in the USA [68].…”

Assessment of the Epidemiology and Burden of Measles in Southern Mozambique

“…14,16 In addition, recent serosurveys have shown that almost one-third of infants < 9 months of age are susceptible to infection, particularly during the "window of vulnerability" (~4-8 months of age) when maternal antibodies have fallen to non-protective levels and infants have not yet been vaccinated. 17,18 Mozambique has a high HIV prevalence with an estimated 13% of the population (≥ 15 years of age) infected in 2007. 19 Maternal HIV infection has various effects on the infant including a decrease in the placental transfer of measles protective antibody.…”