ブラジル、2022年から2023年にかけての小児用第2回COVID-19ワクチン接種率の傾向と空間分布：時間的分析

To investigate the trend and spatial distribution of pediatric second-dose COVID-19 vaccination coverage among children aged 5 to 11 years in Brazil, in 2022 and 2023.

This was a time series analysis study using vaccination and target population data extracted from the Ministry of Health Vacinômetro platform. The second-dose coverage trend was estimated by joinpoint regression (segmented regression), while spatial distribution was analyzed using choropleth maps to identify regional variations between the Brazilian states.

Average monthly percentage change (AMPC) in vaccination coverage in Brazil as a whole remained stable during the period (AMPC -8.30%), with significant geographical heterogeneity. The Northern region (AMPC 5.76%) had a rising trend, in particular in the states of Acre (AMPC 23.42%) and Amazonas (AMPC 18.26%). Falling trends were observed in the Southeast region (AMPC -8.30%) as well as in specific states, such as Mato Grosso do Sul (AMPC -4.74%), Pará (AMPC -4.71%) and Rio de Janeiro (AMPC -4.27%). Fourteen states (51.9%) had a stable trend. The time series revealed initial increase in 2022, followed by deceleration and stabilization in 2023.

A significant and uneven variation in pediatric second-dose COVID-19 vaccination coverage was observed between 2022 and 2023. The results highlight the urgent need for targeted strategies to increase vaccination adherence, especially in areas with lower coverage.