Out-of-sequence DTP and measles vaccinations and child mortality in Guinea-Bissau: a reanalysis.
BMJ Open
; 9(9): e024893, 2019 09 05.
Article
in En
| MEDLINE
| ID: mdl-31492774
ABSTRACT
OBJECTIVES:
To assess whether the sequence of diphtheria-tetanus-pertussis vaccine (DTP) and measles vaccine (MV) was associated with child survival in a dataset previously used to assess non-specific effects of vaccines with no consideration of vaccination sequence.DESIGN:
Prospective cohort study analysed using the landmark approach.SETTING:
Bandim Health Project's Health and Demographic Surveillance System covering 100 village clusters in rural Guinea-Bissau. The recommended vaccination schedule was BCG and oral polio vaccine (OPV) at birth, DTP and OPV at 6, 10 and 14 weeks, MV at 9 months and booster DTP and OPV at 18 months of age.PARTICIPANTS:
Children aged 9-17 months (main analysis) and 18-35 months (secondaryanalysis:
age of booster DTP) with vaccination status assessed between April 1991 and April 1996.METHODS:
Survival during the 6 months after assessing vaccination status was compared by vaccination sequence in Cox-proportional hazards models with age as underlying time. Analyses were stratified by sex and village cluster. MAIN OUTCOMEMEASURE:
Mortality rate ratio (MRR) for out-of-sequence vaccinations compared with in-sequence vaccinations.RESULTS:
Among children aged 9-17 months, 60% of observations (3574/5937) were from children who had received both MV and DTP. Among these, 1590 observations were classified as in-sequence vaccinations (last DTP before MV), and 1984 observations were out-of-sequence vaccinations (1491 MV with DTP and 493 MV before DTP). Out-of-sequence vaccinations were associated with higher mortality than in-sequence vaccinations (MRR 2.10, 95% CI 1.07 to 4.11); the MRR was 2.30 (95% CI 1.15 to 4.58) for MV with DTP and 1.45 (95% CI 0.50 to 4.22) for DTP after MV. Associations were similar for boys and girls (p=0.77). Between 18 and 35 months the mortality rate increased among children vaccinated in-sequence and the differential effect of out-of-sequence vaccinations disappeared.CONCLUSION:
Out-of-sequence vaccinations may increase child mortality. Hence, sequence of vaccinations should be considered when planning vaccination programmes or introducing new vaccines into the current vaccination schedule.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Diphtheria-Tetanus-Pertussis Vaccine
/
Immunization Schedule
/
Immunization, Secondary
/
Vaccination
/
Child Mortality
Type of study:
Observational_studies
Limits:
Child
/
Child, preschool
/
Female
/
Humans
/
Infant
/
Male
Country/Region as subject:
Africa
Language:
En
Journal:
BMJ Open
Year:
2019
Document type:
Article
Affiliation country:
Dinamarca