Association of mRNA COVID-19 vaccination and reductions in Post-COVID Conditions following SARS-CoV-2 infection in a US prospective cohort of essential workers.

Background: While there is evidence that COVID-19 vaccination protects against development of post-COVID conditions (PCC) after severe infection data are limited on whether vaccination reduces the risk after cases of less-severe non-hospitalized COVID-19 disease with more recent SARS-CoV-2 variant viruses. This study assessed whether COVID-19 vaccination was protective against subsequent development of PCC in persons with predominantly mild initial infections during both Delta and Omicron variant predominance.

Methods: This study utilized a case-control design, nested within the HEROES-RECOVER cohort. Participants aged ≥18 years with PCR-confirmed SARS-CoV-2 infection between 6/28/2021 and 9/14/2022 were surveyed for PCC, defined by symptoms lasting >1 month after initial infection Cases were participants self-reporting PCC and controls were participants that did not self-report PCC. The exposure was mRNA COVID-19 vaccination (2 or 3 monovalent doses) versus no COVID-19 vaccination. Logistic regression was used to compare the odds of PCC among vaccinated and unvaccinated persons; additional analyses evaluating PCC subtypes were also performed.

Results: A total of 936 participants with documented SARS-CoV-2 infection were included; of these 23.6% (221) reported PCC and 83.3% (779) were vaccinated. Participants who received a 3rd COVID-19 monovalent mRNA dose prior to infection had lower odds of PCC-related gastrointestinal, neurological, and other symptoms compared to unvaccinated participants (aOR: 0.37; 95% CI: 0.16-0.85; aOR: 0.56; 95% CI: 0.32-0.97; aOR:0.48; 95% CI: 0.25-0.91).

Conclusions: COVID-19 vaccination protected against development of PCC among persons with mild infection during both Delta and Omicron variant predominance, supporting vaccination as an important tool for PCC prevention.