Measles Vaccination After Third Dose of DTP Vaccine May Improve Child Survival
The proportion of children vaccinated with measles vaccine after the third dose of diphtheria-tetanus-pertussis increased from 45% in 1996 to 95% in 2012.
Findings reported in the Frontiers in Public Health suggest that measles vaccines (MV), administered in the recommended sequence, are associated with greater child survival.
Receiving the MV after the third dose of diphtheria-tetanus-pertussis (DTP3) has been shown to be associated with lower mortality than receiving MV first or simultaneously with DTP. Further, receiving MV after DTP3 may also lead to better survival, irrespective of the timing of the measles vaccination.
A follow-up study involving annual cohorts of children (9-23 months of age) from 1996 to 2012 assessed survival in relation to MV status within the first 12 months from the interview date until 5 years of age in Navrongo, Ghana.
A total of 38,333 children were included, and the proportion of children vaccinated with MV after DTP3 increased from 45% in 1996 to 95% in 2012. Compared with MV-after-DTP3 vaccinated children, the adjusted hazard ratio (HR) for unvaccinated children was 1.38 (1.15-1.66) in the first 12 months and 1.22 (1.05-1.41) with follow-up to 5 years of age. For 12 months of follow-up, the HR before national vaccine campaigns for an MV-unvaccinated child was 1.63 (1.23-2.17) compared with MV-after-DTP3. This dropped to an HR of 1.23 (0.97-1.54) after the campaign.
In 1989, only 7% of children in the study area had MV-after-DTP3, and investigators concluded that "the increase in MV-after-DTP3 coverage from 1989 to 2012 may have lowered mortality rate among children aged 9 months to 3 years by 24%."
However, estimates may be conservative because of MV unvaccinated children receiving the MV sometime during follow-up and because of the occurrence of national oral polio vaccine and MV campaigns during the time investigators conducted their annual survey.
Together, this "would tend to minimize the difference in mortality between MV-after-DTP3 and MV-unvaccinated" children. Second, as this was an observational study, many confounding factors could not be controlled, such as general improvements to healthcare delivery, literacy, and infrastructure.
Despite these limitations, there is a clear association with MV-after-DPT3 and reductions in mortality, leading investigators to recommend that "we should continue to vaccinate with MV because of its beneficial effect in improving child survival" even if measles is eliminated.
Welaga P, Hodgson A, Debpuur C, et al. Measles vaccination supports millennium development goal 4: increasing coverage and increasing child survival in Northern Ghana, 1996-2012 [published online February 12, 2018]. Front Public Health. doi: 10.3389/fpubh.2018.00028