title: Reduced childhood mortality after standard measles vaccination at 4-8 months compared with 9-11 months of age.
abstract: OBJECTIVE
  To evaluate the impact on mortality of standard Schwarz measles immunisation before 9 months of age.
  
  
  METHODS
  Children vaccinated in 1980-3 at 4-5, 6-8, and 9-11 months of age were followed to migration, death, or the age of 5 years.
  
  
  METHODS
  One urban district and nine villages in two rural areas of Guinea-Bissau.
  
  
  METHODS
  307 children vaccinated at 4-8 months and 256 at 9-11 months.
  
  
  METHODS
  Mortality from 9 months to 5 years of age for children immunised at 4-5, 6-8, and 9-11 months.
  
  
  RESULTS
  Mortality was significantly lower in children vaccinated at 6-8 months than at 9-11 months (mortality ratio = 0.63, (95% confidence interval 0.41 to 0.97), p = 0.047). As vaccination was provided in semiannual or annual campaigns it is unlikely that age at vaccination reflected a selection bias. The trend was the same in all three study areas. Improved survival after early immunisation was not related to better protection against measles infection. With a Cox multivariate regression model to adjust for age, sex, season at risk, season at birth, measles infection, and region, children vaccinated at 4-8 months had a mortality ratio of 0.61 (0.40 to 0.92, p = 0.020) compared with children vaccinated at 9-11 months. Reimmunised children tended to have lower mortality than children who received only one vaccine (0.59 (0.28 to 1.27, p = 0.176)).
  
  
  CONCLUSIONS
  Standard measles vaccination before 9 months is not associated with higher childhood mortality than is the currently recommended strategy of immunising from 9 months, and it may reduce mortality. This has implications for measles immunisation strategy in developing countries.
authors.affiliation: Epidemiology Research Unit, Statens Seruminstitut, Copenhagen, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Aaby
authors.forename: M
authors.initials: M
authors.lastname: Andersen
authors.forename: M
authors.initials: M
authors.lastname: Sodemann
authors.forename: M
authors.initials: M
authors.lastname: Jakobsen
authors.forename: J
authors.initials: J
authors.lastname: Gomes
authors.forename: M
authors.initials: M
authors.lastname: Fernandes
mesh_terms: D000367:Age Factors; D003906:Developing Countries; D005260:Female; D005500:Follow-Up Studies; D006169:Guinea-Bissau / Q000453:epidemiology; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D008297:Male; D008457:Measles / Q000517:prevention & control*; D008458:Measles Vaccine / Q000008:administration & dosage*; D009026:Mortality; D012959:Socioeconomic Factors; D014611:Vaccination
chemical_list: D008458:Measles Vaccine