Following recovery from COVID-19, more people in the UK are reporting increased vigilance and new side effects, collectively termed post-COVID conditions by the National Institute for Health and Care Excellence. While severe acute symptoms of COVID-19 have been well-documented, the return of distress after the acute phase subsides remains poorly understood. This study aimed to investigate the recurrence of troubling symptoms and clinically significant depression over a 12-week period post-SARS-CoV-2 infection. We systematically searched PubMed, Ovid Medline, and Google Scholar for studies published between January 1, 2020, and June 5, 2021. Recurrence rates and factors contributing to post-COVID conditions were assessed through a combination of case reports. For prospective cohort studies, we used a modified version of the Newcastle-Ottawa Scale to evaluate study quality and bias risk. Of the 316 publications identified, eight studies met our inclusion criteria.
After 12 weeks, the recurrence of severe post-COVID symptoms increased from 11% to 28%. Recurrence of clinically significant depression and other severe debilitating symptoms rose from 3% to 12%. The reappearance of troubling symptoms did not correlate with the severity of initial COVID-19 illness. However, there was substantial variation among studies regarding patient demographics, follow-up duration, assessment timing, and diagnostic methods. Most studies lacked control groups not exposed to COVID-19. Future research should focus on establishing standardized criteria for post-COVID conditions and include unexposed control groups to better understand the disease progression.
