Prevalence of persistent symptoms at least 1 month after SARS-CoV-2 Omicron infection in adults.

Background: Persistent post-COVID-19 symptoms pose an important health care burden. The Omicron variant has rapidly spread across the world and infected millions of people, largely exceeding previous variants. The potential for many of these people to develop persistent symptoms is a major public health concern. The aim of this study was to determine the prevalence and risk factors of post-COVID-19 symptoms associated with Omicron.

Methods: We conducted a single-centre prospective observational study in Quebec, Canada, between December 2021 and April 2022. Participants were adults enrolled in the Biobanque Québécoise de la COVID-19 (BQC19). Cases were considered Omicron cases as more than 85% were estimated to be attributable to Omicron variant during that period. Adults with polymerase chain reaction (PCR)-confirmed COVID-19 were recruited at least 4 weeks after the onset of infection.

Results: Of 1,338 individuals contacted, 290 (21.7%) participants were recruited in BQC19 during that period. Median duration between the initial PCR test and follow-up was 44 days (IQR 31-56 d). A total of 137 (47.2%) participants reported symptoms at least 1-month post-infection. The majority (98.6%) had a history of mild COVID-19 illness. Most common persistent symptoms included fatigue (48.2%), shortness of breath (32.6%), and cough (24.1%). Number of symptoms during acute COVID-19 was identified as a risk factor for post-COVID-19 symptoms (OR 1.07 [95% CI 1.03% to 1.10%] p = 0.009).

Conclusions: This is the first study reporting the prevalence of post-COVID-19 symptoms associated with Omicron in Canada. These findings will have important implications for provincial services planning.