Reduction in Long COVID Symptoms and Symptom Severity in Vaccinated Compared to Unvaccinated Adults
Hannah E. Maier, Theresa Kowalski-Dobson, Ashley Eckard, Carmen Gherasim, David M. Manthei, Alyssa Meyers, Dawson Davis, Kevin Bakker, Kathleen Lindsey, Zijin Chu, Lauren Warsinske, Matthew Arnold, Anna Buswinka, Emily Stoneman, Riccardo Valdez, Aubree Gordon
Abstract
Abstract Background The impact of vaccination prior to infection on postacute sequelae of coronavirus disease 2019 (COVID-19, PASC), also known as long COVID, remains unclear. Here we assess the protective effect of vaccination on long COVID in a community-based setting. Methods The Immunity Associated with SARS-CoV-2 (IASO) study is an ongoing prospective cohort of working adults that began in October 2020. Participants are actively followed for severe acute respiratory syndrome coronavirus 2 infection. We compared the prevalence of symptoms and symptom severity in vaccinated compared to unvaccinated cases. Our primary definition of long COVID was the presence of symptoms at 90 days postinfection; 30 days postinfection was also examined. Results Overall, by 90 days postinfection, 13% of cases had long COVID, with 27% of unvaccinated cases and 8% of vaccinated cases reporting long COVID (relative risk [RR], 0.31 [95% confidence interval {CI}, .22–.42]). Vaccination was also associated with significantly lower average severity scores at all timepoints (eg, relative severity at 90 days postinfection: −2.70 [95% CI, −1.68 to −3.73]). In the pre-Omicron era, 28% of unvaccinated cases and 18% of vaccinated cases reported long COVID (P = .07), and vaccinated cases reported less severe symptoms including less difficulty breathing (P = .01; 90-day RR, 0.07). Conclusions Vaccinated cases had lower prevalence of long COVID and reduced symptom severity.