How Well Do COVID-19 Vaccines Work to Prevent Post–COVID-19 Condition?

The effectiveness of COVID-19 vaccines at preventing post–COVID-19 condition (PCC) has been estimated to vary from 13% to 52% due to heterogeneous study methodologies and case definitions. Now, in a population-based observational study in Sweden (where a PCC diagnosis code has been in use since October 2020), investigators analyzed data on PCC, vaccination history, preexisting comorbidities, COVID-19 severity, and sociodemographic variables in patients with COVID-19 diagnoses between December 2020 and February 2022. In adjusted analysis of vaccination prior to SARS-CoV-2 infection, the authors assessed the effectiveness of such vaccination at preventing PCC.

The cohort consisted of 589,722 patients with COVID-19, of whom 49% had not been vaccinated before infection (median follow-up beginning 28 days after the COVID-19 index date, 129 days). Unvaccinated individuals were primarily infected during the Alpha variant period (60.2%), while vaccinated persons were mostly infected during Omicron's predominance (74.9%). Effectiveness at preventing PCC of at least one dose of vaccine was 58% and rose with the number of doses (21% [1 dose], 59% [2 doses], and 73% [≥3 doses]).