Socioeconomic status correlates with COVID-19 vaccination coverage among primary and secondary students in the most populated city of Chile

Abstract

The burden of COVID-19 was heterogeneous, indicating that the effects of this disease are synergistic with both other non-communicable diseases and socioeconomic status (SES), highlighting its syndemic character. While the appearance of vaccines moderated the pandemic effects, their coverage was heterogeneous too, both when comparing different countries, and when comparing different populations within countries. Of note, once again SES appears to be a correlated factor. 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. Vaccination data was compiled per school type, either public, state-subsidized, or private, at three different dates during the COVID-19 pandemic to cover the dispersion of Delta, Omicron, and its 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. The percentage of school-age children who received vaccinations against COVID-19 correlates with SES. This strong correlation is observed in public and state-subsidized schools, but not in private schools. Although inequity in vaccination coverage decreased over time, it remained higher among students enrolled either in public or state-subsidized schools compared to those of private schools. Although available data was insufficient to explore plausible causes behind lower vaccination coverage, 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 limited access to vaccines for lower-income people, may all have contributed. These findings raise the need to design better strategies to overcome shortcomings in vaccination campaigns to confront future pandemics.

Keywords: COVID-19; Children vaccination; Inequality; Vaccination.

Fig. 1

Correlation between school vaccination coverage and SES Indices in Santiago, Chile as of May 26, 2022. Panel A), municipalities are colored according to their school vaccination coverage and their Community Development Index (CDI) in a Bivariate Map. Municipalities are numbered according to their rank in CDI from higher to lower values. The color coding is shown adjacent to the map using a 3 by 3 matrix where the CDI increases from left to right and the vaccination coverage increases from bottom to top. The values are grouped into three levels. The number labeled in each municipality is sorted by decreasing ranking according to the CDI and can be seen in Table 1. (B) The correlation value between six SES Indices and the median school vaccination coverage was evaluated in the 34 municipalities of the Metropolitan Area of Santiago, Chile. ρ = Spearman’s rank correlation coefficient; p = p-value.

Fig. 2

Correlation between school vaccination coverage and SES Indices by school category in the Metropolitan Area of Santiago as of May 26, 2022. All maps represent Municipalities from the Metropolitan Area of Santiago. They appear colored according to their school vaccination coverage and their Community Development Index (CDI) in a Bivariate Map. Municipalities are numbered according to their rank in CDI from higher to lower values. The color coding is shown adjacent to the map using a 3 by 3 matrix, where the CDI increases from left to right and the vaccination coverage increases from bottom to top. The values are grouped into three levels. The number labeled in each municipality is sorted following a decreasing ranking according to the CDI, as can be seen in Table 1. Next to each map, the correlation of six SES indices and the median school vaccination coverage is show. ρ = Spearman’s rank correlation coefficient; p = p-value. (AB) Public schools’ data. (CD) Private subsidized schools’ data. (EF) Private schools’ data.

Fig. 3

Inequity assessment of COVID-19 vaccination coverage in Santiago, Chile. The Gini coefficient is used to evaluate the inequity of the vaccination coverage for each school type at three time points along the COVID-19 pandemic: on November 15, 2021; March 1st, 2022; and May 26, 2022, covering the spread of different SARS-CoV-2 variants: Delta, Omicron and Omicron BA.4-BA.5, respectively. While inequity in vaccination coverage within schools’ type tend to diminish over time, it is always lower in private schools. The same pattern but with even higher inequity is found when considering the whole country.