The Covid-19 pandemic has wreaked havoc worldwide, but Korea emerged as a model of effective policy measures and public compliance. Citizens masked up and adhered to government directives, achieving lower infection rates and fatalities compared to many other countries.

Yet, as quarantine measures shifted and the virus continued its spread, a new question arose among a group of researchers in Korea: Were health disparities based on socioeconomic status widening? 

Initially, the pandemic's impact seemed uniform across all social strata. However, as the crisis evolved, differences in health outcomes began to surface.

Professor Lee Hye-jin from the Department of Family Medicine at Seoul National University Bundang Hospital (SNUBH)'s research team, including Professor Lee Jin-yong from the Public Healthcare Center at Seoul National University Hospital (SNUH) and student Nam Hyun-woo from Seoul National University College of Medicine, recently examined whether these disparities developed over the three-year course of the pandemic. Conducting an in-depth study,  they sought to investigate the potential socioeconomic health disparities associated with Covid-19 in Korea. 

Their findings, published on March 13 in the journal Epidemiology and Health, reveal that medical aid recipients had lower Covid-19 incidence rates than higher-income groups but exhibited higher rates of hospitalization, mortality, and fatality.

Analyzing data from the National Health Insurance Service (NHIS), encompassing over 51 million individuals from January 2020 to December 2022, the research team divided the timeline into four phases, each reflecting shifts in government quarantine policies. They examined each phase's incidence, hospitalization, mortality, and fatality rates. 

Their findings revealed that out of 21,105,865 people, or 40.6 percent of the population, who contracted Covid-19 at least once, the majority of infections occurred during phase 3 (November 2021 to May 2022) and phase 4 (June 2022 to December 2022). The overall death toll reached 54,638, with mortality rates rising in the later stages of the pandemic, and fatality rates higher in the early stages. 

A closer look at the data revealed a trend where medical aid recipients, often representing lower-income groups, had a lower incidence of Covid-19 but faced significantly higher rates of hospitalization, mortality, and fatality compared to their higher-income counterparts. As the pandemic progressed, these disparities widened.

During phase 1, medical aid recipients had a higher incidence rate (328 per 100,000) compared to the average (186 per 100,000). Hospitalization rates were alarmingly high throughout the study, peaking at 5,663 per 100,000, more than double the average. Mortality rates for medical aid recipients were 4.7 times higher, and their fatality rates were nearly six times higher than those with medical insurance.

The research team also identified other vulnerable groups: individuals with disabilities, multiple comorbidities, males, older adults, and residents outside metropolitan areas. Members of these groups faced a higher risk of hospitalization and death.

“Korea may have maintained a low fatality rate for Covid-19 across all income levels, but vulnerable groups are more susceptible to the disease,” Professor Lee of SNUBH said. “It is crucial to establish response strategies and social safety nets to prevent health inequalities for vulnerable populations in future infectious disease outbreaks.”

The study also underscored the need for targeted public health interventions. Medical aid recipients faced a 2.55 times higher risk of hospitalization, and individuals with disabilities were 1.85 times more likely to be hospitalized. Vaccination proved to be a critical factor, reducing hospitalization risk significantly.

"The health impacts of Covid-19 in Korea were previously analyzed only in fragments,” said Professor Lee  of SNUH. As the world continues to brace for future public health crises, Professor Lee added, “Learning from the Covid-19 experience can help us better address upcoming challenges."

The full study detailing these findings is published in Epidemiology and Health.