Lower vaccination coverage against COVID-19 in school-aged children is associated with low socioeconomic status in the Metropolitan Area of Santiago, Chile

Background The burden of COVID-19 has been heterogeneous, indicating that the effects of this disease are synergistic with both other non-communicable diseases and socioeconomic status (SES), high-lighting its syndemic character. While the appearance of vaccines has moderated the pandemic effects, their coverage has also been heterogeneous, both when comparing different countries, and when comparing different populations within countries. Of note, once again SES appears to be a correlated factor.

Methods To examine the relationship between SES and vaccination coverage, we analyzed publicly available data detailing the percentage of school-aged vaccinated children in different municipalities belonging to the Metropolitan Area (MA) of Santiago, Chile, one of the most largely vaccinated countries in the world. Vaccination data was compiled per school type, either public, state-subsidized and private, at three different dates along the COVID-19 pandemic so to cover the dispersion of Delta, and Omicron, including Omicron subvariants BA.4 and BA.5. We computed the median vaccination ratio for each municipality and school type and calculated their Spearman’s rank correlation coefficient with each one of nine SES indices.

Findings In the MA of Santiago, Chile, the percentage of school-age children who have received vaccinations against COVID-19 correlates with SES. Vulnerable municipalities with low SES exhibit low levels of vaccination coverage. Of note, this strong correlation is observed in both public and state-subsidized schools, but to a meaningless extent in private schools. Although inequity in vaccination coverage decreases over time, it remains higher among students enrolled either in public and state-subsidized schools compared to those of private schools.

Interpretation Available data is insufficient to explore plausible causes behind lower vaccination coverage in vulnerable municipalities in the MA of Santiago, Chile. However, considering the available literature, it is likely that a combination of factors including the lack of proper information about the importance of vaccination, the lack of incentives for children’s vaccination, low trust in the government, and/or limited access to vaccines for lower-income people, may all have contributed to this low vaccination coverage. Importantly, unless corrected, the inequity in vaccination coverage will exacerbate the syndemic nature of COVID-19.