In 2019, when COVID-19 began to spread, we analyzed healthcare accessibility by applying the 2SFCA method using population density and the number of beds in negative pressure isolation rooms (NPIRs) and general isolation rooms. Accessibility to beds was generally high in central Seoul but decreased significantly toward the outer areas of the Seoul Capital Region. 

• Nighttime healthcare service area by travel durations 

During nighttime hours, the number of operating medical facilities decreases sharply, resulting in significantly lower levels of healthcare accessibility compared to daytime. Using the enhanced two-step floating catchment area (E2SFCA) method with a distance-decay function, we measured nighttime healthcare accessibility in Seoul and North Gyeongsang Province, where the number of available medical facilities is relatively limited. 

Seoul recorded the highest number of physicians (18,315) and the highest number of physicians per 1,000 population (1.9) among all metropolitan local governments, while North Gyeongsang ranked mid-range in total physicians (1,795) but had the second-lowest number of physicians per 1,000 population (0.7) nationwide.

The service areas of tertiary and secondary hospitals, those representing the highest levels of care, in Seoul and North Gyeongsang are shown in Figures 4a and 4b.

• Estimated overnight healthcare service demands

The nighttime floating population differs substantially from the resident population. Based on the ratio of credit card medical transactions to the mobile phone nighttime population, the estimated weekday and weekend demand populations are shown above (Fig. 5).

• Spatial accessibility to healthcare service

Differences in healthcare accessibility were observed between weekdays and weekends. In the case of North Gyeongsang, the variation in accessibility scores within the region was notably larger compared to Seoul (Fig 6).