Childhood Immunization and Competing Mortality Risks in Kenya: A Longitudinal Analysis for Multiparous Mothers

To assess the relationship between childhood immunization and mortality risks for nonvaccine-preventable diseases (competing mortality risks, or CMR) in Kenya.

A combination of the Global Burden of Disease and Demographic Health Survey data was used to measure basic vaccination status, CMR, and control variables for each child in the Demographic Health Survey data. A longitudinal analysis was performed. This uses within-mother variation between children to compare the vaccine decisions for different children, who are exposed to different mortality risks. The analysis also distinguishes between overall and disease-specific risks.

The study included 15 881 children born between 2009 and 2013, who were at least 12 months old at the time of interview and not part of a twin birth. Mean basic vaccination rates ranged from 27.1% to 90.2% and mean CMR from 13.00 to 738.32 deaths per 100 000 across different counties. A one-unit increase in mortality risk from diarrhea, the most prevalent disease among children in Kenya, is associated with a 1.1 percentage point decline in basic vaccination status. In contrast, mortality risks for other diseases and HIV increase the likelihood of vaccination. The effect of CMR was found to be stronger for children with higher birth orders.

A significant negative correlation between severe CMR and vaccination status was found, which has important implications for immunization policies, particularly in Kenya. Interventions aimed at reducing the most severe CMR, such as diarrhea, and targeted toward multiparous mothers may improve childhood immunization coverage.