title: Measles incidence, vaccine efficacy, and mortality in two urban African areas with high vaccination coverage.
abstract: Measles incidence, vaccine efficacy, and mortality were examined prospectively in two districts in Bissau where vaccine coverage for children aged 12-23 months was 81% (Bandim 1) and 61% (Bandim 2). There was little difference in cumulative measles incidence before 9 months of age (6.1% and 7.6%, respectively). Between 9 months and 2 years of age, however, 6.1% contracted measles in Bandim 1 and 13.7% in Bandim 2. Even adjusting for vaccination status, incidence was significantly higher in Bandim 2 (relative risk 1.6, P = .04). Even though 95% of the children had measles antibodies after vaccination, vaccine efficacy was not more than 68% (95% confidence interval [CI] 39%-84%) and was unrelated to age at vaccination. Unvaccinated children had a mortality hazard ratio of 3.0 compared with vaccinated children (P = .002), indicating a protective efficacy against death of 66% (CI 32%-83%) of measles vaccination. These data suggest that it will be necessary to vaccinate before age 9 months to control measles in hyperendemic urban African areas.
authors.affiliation: Institute of Anthropology, University of Copenhagen, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Aaby
authors.forename: K
authors.initials: K
authors.lastname: Knudsen
authors.forename: T G
authors.initials: TG
authors.lastname: Jensen
authors.forename: J
authors.initials: J
authors.lastname: Thårup
authors.forename: A
authors.initials: A
authors.lastname: Poulsen
authors.forename: M
authors.initials: M
authors.lastname: Sodemann
authors.forename: M C
authors.initials: MC
authors.lastname: da Silva
authors.forename: H
authors.initials: H
authors.lastname: Whittle
mesh_terms: D000367:Age Factors; D000914:Antibodies, Viral / Q000032:analysis; D015331:Cohort Studies; D006169:Guinea-Bissau / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D008457:Measles / Q000453:epidemiology* / Q000276:immunology / Q000401:mortality; D008458:Measles Vaccine / Q000276:immunology; D008459:Measles virus / Q000276:immunology; D011446:Prospective Studies; D012044:Regression Analysis; D014505:Urban Population; D014611:Vaccination
chemical_list: D000914:Antibodies, Viral; D008458:Measles Vaccine