Unequal burdens of COVID-19 infection: a nationwide cohort study of COVID-19-related health inequalities in Korea

Abstract

Objectives: While the Korean government's response to the coronavirus disease 2019 (COVID-19) pandemic is considered effective given the relatively low mortality rate, issues of inequality have been insufficiently addressed. This study explored COVID-19-related health inequalities in Korea.

Methods: Age standardization for various health inequality indices was derived using data from the Korean National Health Insurance Service, the Korea Disease Control and Prevention Agency, and the Microdata Integrated Service of Statistics Korea. The slope index of inequality (SII) and relative index of inequality (RII) were calculated for socioeconomic variables, while absolute difference (AD) and relative difference (RD) were used for gender and disability inequalities.

Results: We observed a number of COVID-19-related health outcome inequalities. Gender inequality was particularly noticeable in infection rates, with the rate of women 1.16 times higher than that of men. In contrast, socioeconomic inequality was evident in vaccination rates, with a 4.5-fold (SII, -4.519; 95% confidence interval, -7.403 to -1.634) difference between the highest and lowest household income groups. Regarding clinical progression post-infection, consistent findings indicated higher risk for men (RD for hospitalization, 0.90; severe cases, 0.54; and fatality, 0.65), individuals with disabilities (RD for hospitalization, 2.27; severe cases, 2.29; and fatality, 2.37), and those from lower socioeconomic groups (SII for hospitalization, 1.778; severe cases, 0.089; and fatality, 0.451).

Conclusions: While the infection risk was nearly ubiquitous, not everyone faced the same level of risk post-infection. To prevent further health inequalities, it is crucial to develop a thoughtful policy acknowledging individual health conditions and resources.

Keywords: COVID-19; Health inequities; Pandemics.

Figure 1.

Age-specific rates of coronavirus disease 2019 (COVID-19)-related health outcomes by gender and age. The solid line with the square mark indicates the age-specific rates of COVID-19-related health outcomes for both men and women. The solid line marked with a diamond shape represents the age-specific rates of COVID-19-related health outcomes in men. The dotted line with the triangular mark represents the age-specific rates of COVID-19-related health outcomes in women.

Figure 2.

Slope index of inequality (SII) for health outcomes based on household income. The square mark represents the value of the SII for each health outcome, while the horizontal line indicates the 95% confidence interval (CI).