Prevalence of long-term effects in individuals diagnosed with COVID-19: a living systematic review

Reyes Domingo, F.; Waddell, L. A.; Cheung, A. M.; Cooper, C. L.; Belcourt, V. J.; Zuckermann, A. M. E.; Corrin, T.; Ahmad, R.; Boland, L.; Laprise, C.; Idzerda, L.; Khan, A.; Jaramillo Garcia, A.

Background: Patients have described symptoms persisting or recurring for weeks after acute COVID-19 illness referred to as post COVID-19 conditions. The objective of this living systematic review is to document the prevalence of post COVID-19 conditions 4-12 weeks (short-term) and >12 weeks (long-term) after COVID-19 diagnosis. Methods: We conducted a systematic review of primary peer-reviewed published literature reporting on the prevalence of the symptoms, sequelae and difficulties conducting usual activities [≥]4 weeks after COVID-19 diagnosis. We adapted a previous search strategy used by the U.K. National Institute for Health and Care Excellence and updated it to search for new research published until January 15, 2021 in Embase, Medline, PsychInfo, and Cochrane Central. Two independent reviewers screened references; one reviewer extracted data and assessed risk of bias and certainty in the evidence while another verified them. Prevalence data from laboratory-confirmed individuals were meta-analyzed, where appropriate, using a random effects model and synthesized separately in the short- and long-term periods after COVID-19 diagnosis; data from clinically-diagnosed populations were synthesized narratively. Results: Of the 2807 unique citations, 36 observational studies met our inclusion criteria. Over 100 post COVID-19 conditions were reported in laboratory-confirmed individuals. Eighty-three percent (95%CI: 65-93%; low certainty) and 56% (95%CI: 34-75%; very low certainty) reported persistence or presence of one or more symptoms in the short- and long-term, respectively. The most prevalent symptoms in both periods included: fatigue, general pain or discomfort, sleep disturbances, shortness of breath and anxiety or depression (point estimates ranging from 22-51%; low to very low certainty). Interpretation: Our data indicate that a substantial proportion of individuals reported a variety of symptoms [≥]4 weeks after COVID-19 diagnosis. Due to low certainty in the evidence, further research is needed to determine the true burden of post COVID-19 conditions.