Trends in coverage following an equity-oriented strategy for introducing new vaccines, Peru, 2004-2022

To evaluate the outcome of Peru's strategy to introduce new vaccines in the poorest regions with high child mortality rates.

We analysed data from nationally representative annual health surveys conducted between 2004 and 2022. We examined associations between vaccine coverage and poverty (proportion of households in the poorest 40% of the national wealth index) at the ecological level using the country's 25 regions and at the individual child level using household wealth quintiles. We obtained vaccination data from home-based records.

The surveys included 49 023 children aged 18-29 months. In the ecological analyses, coverage for Haemophilus influenzae type b, pneumococcal conjugate and rotavirus vaccines was positively associated with poverty prevalence in the initial post-introduction period, but these associations disappeared over time. In contrast, the individual-level analyses indicated that children from wealthier families were consistently more likely to be vaccinated than children from poorer families. In the most recent period (2018-2022), vaccination coverage in the wealthiest quintile was about 10 percentage points higher than in the poorest quintile. Coverage levels for boys and girls were similar. Children whose low-income families were enrolled in the Juntos cash transfer programme had higher coverage than the rest of the population.

The strategy increased coverage in the poorest districts initially and, as national coverage grew, regional disparities were eliminated. However, socioeconomic differences persisted, with wealthier children maintaining higher vaccination rates throughout the study. To eliminate these disparities, geographic targeting should be complemented with household-level targeting.