title: Non-specific effects of diphtheria-tetanus-pertussis and measles vaccinations? An analysis of surveillance data from Navrongo, Ghana.
abstract: OBJECTIVE
  Studies from low-income countries have suggested that routine vaccinations may have non-specific effects on child mortality; measles vaccine (MV) is associated with lower mortality and diphtheria-tetanus-pertussis (DTP) with relatively higher mortality. We used data from Navrongo, Ghana, to examine the impact of vaccinations on child mortality.
  
  
  METHODS
  Vaccination status was assessed at the initiation of a trial of vitamin A supplementation and after 12 and 24 months of follow-up. Within the placebo group, we compared the mortality over the first 4 months and the full 2 years of follow-up for different vaccination status groups with different likelihoods of additional vaccinations during follow-up. The frequency of additional vaccinations was assessed among children whose vaccination card was seen at 12 and 24 months of follow-up.
  
  
  RESULTS
  Among children with a vaccination card, more than 75% received missing DTP or MV during the first 12 months of follow-up, whereas only 25% received these vaccines among children with no vaccination card at enrollment. Children without a card at enrollment had a significant threefold higher mortality over the 2-year follow-up period than those fully vaccinated. The small group of children with DTP3-4 but no MV at enrollment had lower mortality than children without a card and had the same mortality as fully vaccinated children. In contrast, children with 1-2 DTP doses but no MV had a higher mortality during the first 4 months than children without a card [MRR = 1.65 (0.95, 2.87)]; compared with the fully vaccinated children, they had significantly higher mortality after 4 months [MRR = 2.38 (1.07, 5.30)] and after 2 years [MRR = 2.41 (1.41, 4.15)]. Children with 0-2 DTP doses at enrollment had higher mortality after 4 months (MRR = 1.67 (0.82, 3.43) and after 2 years [MRR = 1.85 (1.16, 2.95)] than children who had all three doses of DTP at enrollment.
  
  
  CONCLUSIONS
  As hypothesised, DTP vaccination was associated with higher child mortality than measles vaccination. To optimise vaccination policies, routine vaccinations need to be evaluated in randomised trials measuring the impact on survival.
authors.affiliation: Navrongo Health Research Centre, Navrongo, Ghana  Bandim Health Project, Statens Serum Institut, Copenhagen, Denmark  London School of Hygiene and Tropical Medicine, London, UK  Bandim Health Project, Indepth Network, Bissau, Guinea-Bissau.
authors.forename: Paul
authors.initials: P
authors.lastname: Welaga
authors.forename: Jens
authors.initials: J
authors.lastname: Nielsen
authors.forename: Martin
authors.initials: M
authors.lastname: Adjuik
authors.forename: Cornelius
authors.initials: C
authors.lastname: Debpuur
authors.forename: David A
authors.initials: DA
authors.lastname: Ross
authors.forename: Henrik
authors.initials: H
authors.lastname: Ravn
authors.forename: Christine S
authors.initials: CS
authors.lastname: Benn
authors.forename: Peter
authors.initials: P
authors.lastname: Aaby
mesh_terms: D016022:Case-Control Studies; D046688:Child Mortality; D002675:Child, Preschool; D003906:Developing Countries; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000494:pharmacology*; D005500:Follow-Up Studies; D005869:Ghana / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008458:Measles Vaccine / Q000494:pharmacology*; D016016:Proportional Hazards Models; D016019:Survival Analysis
chemical_list: D015721:Diphtheria-Tetanus-Pertussis Vaccine; D008458:Measles Vaccine