COVID-19 Pandemic
Time to Death as an Indicator of Pandemic Preparedness During COVID-19 in South Korea Suyoung Jo* Suyoung Jo Jo Jo Jo Seoul National University
Background: Although COVID-19 mortality has been extensively studied, little is known about how long health systems were able to sustain individuals after diagnosis during pandemic surges. Time to death after diagnosis may reflect acute health system performance and resilience.
Objective: To quantify host vulnerability, immune burden, and structural health system-mediated factors associated with time to death within 90 days after COVID-19 diagnosis in South Korea.
Methods: We analyzed nationwide linked insurance claims and confirmed case records including 4,971,772 individuals diagnosed between October 2020 and June 2023. Follow-up was administratively censored at 90 days after the most recent diagnosis. Time to death was modeled using an accelerated failure time approach assuming a Weibull distribution. Covariates included age, recent vaccination within six months prior to diagnosis, insurance type, and pandemic period.
Results: A total of 24,326 deaths occurred within 90 days. Increasing age showed a strong graded association; individuals aged 80 years or older had survival times 92% shorter than those aged 20–34 years (95% CI 91%–92%). Marked structural inequities were observed, with medical aid beneficiaries showing survival times 22% shorter than employed insurance holders (95% CI 21%–22%). Individuals without recent vaccination had survival times 15% shorter than those vaccinated within six months (95% CI 14%–15%). Compared with the Omicron period, survival time was 25% longer during the pre-Delta period (95% CI 22%–27%) and 7% longer during the Delta period (95% CI 6%–9%).
Conclusions: Time to death after diagnosis revealed substantial disparities in acute health system performance by baseline host vulnerability, structural health system–mediated inequities, and immune burden. Modeling survival time provides a framework for identifying system-level vulnerabilities relevant to future pandemic preparedness.