Vaccination and the risk of post-acute sequelae after COVID-19 In the Omicron-predominant period.

OBJECTIVES: To assess the association of primary and third doses of vaccination with the risk of post-acute sequelae of COVID-19.

METHODS: This retrospective cohort study utilized a combined database of nationwide healthcare claims data, COVID-19 patient registry, and vaccination records from South Korea. Individuals diagnosed with COVID-19 in the Omicron variant-dominant period of January to March 2022 were tracked for 30-120 days post-infection. The exposure of interest was the receipt of primary and third doses of the SARS-CoV-2 vaccine. The occurrence of 26 specific conditions in eight domains was compared using Cox regression with inverse probability of treatment weighting.

RESULTS: This study included 394,773 unvaccinated individuals and 7,604,081 individuals receiving ≥2 doses of vaccine. Compared with unvaccinated individuals, vaccination with at least two doses was associated with a reduced risk (adjusted hazard ratio; 95% confidence interval) of several conditions, including ischemic heart disease (0.73; 0.57-0.94), heart failure (0.55; 0.48-0.63), cardiac dysrhythmia (0.72; 0.61-0.85), cardiac arrest (0.41; 0.33-0.51), pulmonary embolism (0.66; 0.52-0.84), venous thromboembolism (0.54; 0.44-0.66), acute renal failure (0.56; 0.46-0.67), new dialysis (0.45; 0.34-0.59), chronic obstructive pulmonary disease (0.74; 0.65-0.84), acute pancreatitis (0.64; 0.51-0.80), and diabetes (0.82; 0.71-0.95). The risks of heart failure, cardiac dysrhythmias, cardiac arrest, pulmonary embolism, and new dialysis were lower in those vaccinated with three doses compared with two doses.

CONCLUSIONS: Vaccination was associated with a decreased risk of post-acute sequelae of COVID-19, suggesting its potential role in mitigating the indirect impacts of COVID-19.