A Study to Learn About the Study Medicine Paxlovid (Nirmatrelvir + Ritonavir) in Adults Aged 60 and Older Living in Korean Long-term Care Hospitals Who Have COVID-19

The purpose of this study is to learn about the effects of the study medicine (called Paxlovid) for the possible treatment of COVID-19 in older adults who live in long-term care hospitals (LTCHs) in Korea. Researchers want to know whether Paxlovid lowers the chance of severe illness or death and helps people carry out their usual daily activities, remain free from aging and weakness, and maintain cognitive function.

This study is seeking participants who:

* are 60 years of age or older * live in a long-term care hospital in Korea * were diagnosed with COVID-19 on or after 14 January 2022, during the period when Paxlovid was available as part of routine care * received Paxlovid within 5 days after their first COVID-19 symptoms (only for people in the Paxlovid group)

All participants in this study received their usual COVID-19 care. About half also received Paxlovid. Paxlovid was prescribed as part of routine care at the long-term care hospital, typically taken by mouth 2 times a day for 5 days.

The study team will compare the health results of people who received Paxlovid to those who did not, using similar parameters such as age, sex, and medical history. This will help the study team to understand whether Paxlovid makes a meaningful difference in stopping severe illness, death, or slow-down daily functioning.

Participants will not have any extra study visits or tests. The study team will only review information already recorded in their medical charts for up to 1 year after their COVID-19 symptom onset.