• COVID-19
• Epidemiology

COVID-19 has imposed a significant disease burden on the paediatric population worldwide. Although most infected children experience mild clinical symptoms, SARS-CoV-2 has led to severe infections in those with underlying medical conditions. Several public health agencies globally have issued vaccine recommendations to prevent COVID-19 in children. For instance, the US Centers for Disease Control and Prevention recommends COVID-19 vaccines for all individuals aged 6 months and older.1 Conversely, the European Centre for Disease Prevention and Control has issued a position paper suggesting that children at risk of severe COVID-19 should be considered a priority group for vaccination, implying a risk-based approach to vaccination in children.2 Our objective was to evaluate and compare vaccination and age-specific death rates between Japan and South Korea amid the COVID-19 pandemic. This objective was achieved through a descriptive comparison in an ecological design and by presenting age-specific death rates with CIs. Furthermore, we employed age-specific death rate ratios between the two countries to investigate the correlation between vaccination strategies and age-specific death rates.

Japan and South Korea possess similar healthcare systems based on public health insurance, facilitating easy access to paediatric care. Both countries exhibit similar life expectancy at birth (Japan 83.4 years vs Korea 81.9 years), similar infant mortality rates (Japan 2.1 vs Korea 3.0) and under-5 mortality rates (Japan 3.0 vs Korea 4.0).3 Routine vaccination schedules recommended by the Japan Pediatric Society and the Korean Pediatric Society are similar. In response to the COVID-19 pandemic, both countries implemented similar policies, including social distancing measures. However, their approaches to vaccination for children were different: Japan adopted a universal recommendation for COVID-19 vaccination for all children, whereas Korea’s recommendation prioritised children with high-risk conditions, following risk-based recommendations.

Table 1 shows a brief comparison of COVID-19 vaccination approaches in children and coverage and death rates in Japan (https://COVID-19.mhlw.go.jp/) and Korea (https://ncov.kdca.go.kr/). In Japan, the vaccine coverage rates (for at least one dose) were 19% for children aged 5–11 years and 72% for children aged 12–19 years; whereas in Korea, the coverage rates were lower, at 2% (5–11 years) and 55% (12–17 years). The age-specific death rates were 0.43 per 100 000 (95% CI 0.31 to 0.58) in the Japanese 0–9 years group and 1.07 per 100 000 (95% CI 0.75 to 1.43) in the Korea 0–9 years age group. The Korea-to-Japan ratios (K-to-J) for child mortality were 2.49 (95% CI 1.59 to 3.90) in the 0–9 years age group and 2.58 (95% CI 1.64 to 4.04) in the 10–19 years age group. In adults aged ≥20 years, the death rates were 58.33 per 100 000 (95% CI 57.87 to 58.79) in Japan and 80.34 (95% CI 79.50 to 81.19) in Korea, resulting in a K-to-J ratio of 1.38 (95% CI 1.35 to 1.39). In both Japan and Korea, children typically do not have assigned paediatricians, allowing them the freedom to choose a paediatrician on a case-by-case basis. While this approach ensures responsive care during acute illnesses, it may lack a specific mechanism for identifying ‘risk factors’ in children, thus hindering the delivery of personalised preventive services, as outlined in a ‘risk-based’ vaccination guideline.4 The clinical implications drawn from this systematic review indicate that the decision to vaccinate children against COVID-19 entails complexity and nuance. The key findings highlight the necessity of meticulously evaluating the risk–benefit ratio, particularly in light of the comparatively mild cases and lower risk of severe outcomes in children than in adults. Consistent with the findings of this study, our perspective underscores the importance of exercising caution in determining the necessity of childhood COVID-19 vaccination. Clinicians and policy-makers are urged to carefully consider various factors, including disease burden, academic considerations, ethical concerns, uncertainties around community transmission and long-term effects, to make informed decisions regarding the vaccination of children against COVID-19.

Although we aimed to provide insights into the comparative analysis of vaccination strategies for children amid the COVID-19 pandemic, we acknowledge a limitation associated with the selection of indicators. In this ecological study, we compared age-specific death rates, recognising that these rates may include causes of death unrelated to the SARS-CoV-2 infection, potentially introducing a selection bias. Age-specific excess mortality directly attributable to SARS-CoV-2 infection would serve as a more precise indicator.

The absence of a mechanism to identify children’s individual risk factors and customise vaccine recommendations accordingly indicates that a risk-based vaccine strategy may not offer sufficient protection to children. In contrast, a universal vaccination strategy has emerged as a more effective tool for systematically reducing mortality and morbidity in children during future pandemics.