Introduction

Since the first cases of coronavirus disease 2019 (COVID-19) appeared in Wuhan, China, morbidity and mortality by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been significant in countries in every continent. Mortality is mostly concentrated in advanced age groups and the adult population with ongoing comorbidities¹-⁵. Children and adolescents constitute 2% and 9.5% of all reported cases in Europe and the USA. Severe COVID-19 is infrequent in children, so intensive care unit admissions regarding this age group have been reported to be about 2% and mortality rate about 0.08%⁶. Besides, preliminary evidence suggests that both ethnicity (Black and Hispanic) and age (under 1 month and early adolescence [10-14 years]) are associated with admission to a critical care unit. Moreover, children from low-income families or non-White ethnicities are more likely to test positive for SARS-CoV-2 than White children and high-income families⁷,⁸.

Although some countries have published COVID-19 epidemiologic data in the pediatric population, the comparison among different populations is scarce. COVID-19 mortality in the population under 18 years of age might be heterogeneous between countries with different incomes and ethnicities. This brief report aimed to explore international differences in the COVID-19 pediatric mortality rate.

Methods

We included information about countries with populations over 5 million that reported COVID-19 deaths disaggregated by quinquennial or decennial age groups. Data on confirmed COVID-19 death counts were consulted in the COVID-19 cases and deaths by age database (COVerAge-DB)⁹. COVerAge-DB collects age- and sex-specific cumulative cases, deaths, and tests from official reports from multiple countries worldwide and several subpopulations. Data from Argentina, Canada, Peru, and Mexico were consulted from the local ministries of health¹⁰-¹³. Data from countries disaggregated by decennial age groups were estimated according to the countries’ age structure available data.

For the computation of age-specific mortality rates, we obtained both total and quinquennial age groups estimated populations for 2018 or the latest available year from the United Nations Statistics Division web site¹⁴. Data for general COVID-19 mortality were extracted from the World Health Organization reports¹⁵.

In an exploratory analysis, we also calculated the Spearman’s correlation coefficient between pediatric COVID-19 mortality rates with general mortality rates and newborn mortality by any cause in 2018 (before the COVID-19 pandemic). STATA 13.0 ® software was used for the analysis.

Results

We included 23 countries in the analysis. Table 1 shows the general mortality and pediatric mortality rates from COVID-19. Specifically, 63% of deaths in the < 15 years of age population at the time of the study occurred in India (n = 1,622). However, when adjusting the mortality per million people for this age group, the highest rates were observed in Latin American countries (Peru, Brazil, Ecuador, and Mexico). Peru showed the highest overall COVID-19 mortality rate followed by European countries (the United Kingdom, Spain, and Italy). Furthermore, the highest pediatric to general population ratio of COVID-19 mortality was identified in Asian countries (India, Indonesia, and the Philippines).

Table 2 shows COVID-19 pediatric mortality by quinquennial age groups. The highest mortality in children under 10 years old was observed in Peru, and the highest mortality in children > 10 years old was in Brazil.

We found a significant correlation between both COVID-19 pediatric mortality and COVID-19 pediatric/general mortality ratio and neonatal mortality in 2018 (r = 0.77, p < 0.001; and r = 0.88, p < 0.001, respectively), while a moderate or no correlation was found with COVID-19 mortality in the general population (r = 0.47, p = 0.02; and r = 0.19, p = 0.38, respectively) (Table 3).

Discussion

COVID-19 mortality in children is minimal in comparison to the adult population. However, we found significant heterogeneity between countries. Several factors should be explored to explain this variability. This report was elaborated with available data from different sources, and differences in reporting systems of epidemiological information may be accountable for some variation.

Remarkably, the highest pediatric mortality rates are among upper-middle-income countries in contrast with high-income countries (data for low- and lower-middle-income countries were not available). Similarly, high-income countries with high mortality rates in the general population showed low COVID-19 pediatric/general mortality rate ratio (adjusted for age).

In most countries, the pediatric population’s COVID-19 mortality rate is concentrated in the < 5-year-old population. Brazil has a disproportionately high mortality rate in adolescents, and the causes of this must be studied. In Mexico, about half of the deaths in the 0-4 age group are in infants < 1 year old. It is important to disaggregate data by age to estimate the share of child mortality, which corresponds to neonatal and infant mortality.

Child, infant, and neonatal mortality are known indicators of the quality of health-care systems¹⁶. It is noticeable that COVID-19 pediatric mortality and COVID-19 pediatric/general rate ratio are strongly correlated with historical basal neonatal mortality, while they are only moderately correlated with COVID-19 general mortality. These findings suggest an important role of social health determinants and the quality of health-care systems in discrepancies of COVID-19 pediatric mortality rates between countries. The relative importance of this set of factors over biological factors remains to be established.