Vaccines are one of the best buys in public health. However, worldwide, 17.1 million children did not receive at least one dose of the three-dose diphtheria–tetanus–pertussis (DTP) series. Major global immunization initiatives have adopted an intensified focus on reaching zero-dose children (operationalized as children with zero doses of DTP).

We quantified the extent of socioeconomic inequality and change over time in zero-dose DTP prevalence using 156 household surveys conducted between 2010 and 2019 in 89 low- and middle-income countries.

We found 8% of children failed to receive any doses of DTP. In most countries, zero-dose DTP prevalence was twice as high among the poorest children than in the wealthiest. The highest socioeconomic inequality was found in low-income countries where the prevalence of zero-dose DTP was 21% in the poorest children, while it was 6% in the wealthiest.

Over a period of ten years, the national zero-dose DTP prevalence declined by 2 percentage points (pp). In the same period, there was a decline of 1.6 pp in the poorest children and 0.4 pp in the wealthiest.

Our analysis serves as an important baseline assessment to benchmark future efforts to reduce the number of zero-dose children. Socioeconomic inequalities in zero-dose children, alongside other dimensions of inequality, should be monitored regularly as new data become available.

These results were published in the Vaccines Journal as open access and you can find it here: Vaccines 2022