Effect of COVID-19 Vaccination and SARS-CoV-2 Infection Status on Mortality Risk in Patients with Chronic Obstructive Pulmonary Disease: a Nationwide Population-Based Cohort Study

The coronavirus disease 2019 (COVID-19) vaccination is suggested to be effective in improving outcomes of chronic obstructive pulmonary disease (COPD). However, real-world evidence on long-term mortality among individuals with COPD, accounting for both vaccination and COVID-19 infection status, remains sparse. A retrospective cohort study was conducted using datasets from the Korean National Health Insurance system. Through two-step propensity score matching, 716 individuals with COPD were included in the analysis and classified into four groups according to COVID-19 vaccination and severe acute respiratory syndrome coronavirus 2 infection status: 125 COVID-19 vaccinated/uninfected, 125 vaccinated/infected, 233 unvaccinated/uninfected, and 233 unvaccinated/infected. A multivariable Cox proportional hazards regression analysis was conducted to assess the risk of mortality following COVID-19 vaccination and SARS-CoV-2 infection status. The median follow-up period was 420 days, during which 79.6