Post-acute effects of SARS-CoV-2 infection in individuals not requiring hospital admission: a Danish population-based cohort study

SPS commentary:

There was no increased risk (absolute risk difference <0·1%) of initiating 11 selected drug therapies or receiving one of 25 selected new hospital diagnoses considered potential post-acute effects of SARS-CoV-2 infection, in the 2 weeks to 6 months after a SARS-CoV-2 test, for those who tested positive compared with those who tested negative Slightly increased risks were identified for initiating bronchodilating agents (risk difference +0·3%), specifically short-acting β-2 agonists (+0·4%), and triptans (+0·1%), and for new hospital diagnoses of dyspnoea (+0·6%) and venous thromboembolism (+0·1%).

According to a commentary, the authors only investigated six persisting symptoms, which did not cover the whole potential clinical spectrum and the prevalence of the persistent symptoms in patients with COVID-19 was about 1%, which was lower than that in a previous study, which showed a rate of 5–15%. It suggests that given the inherent nature of this type of registration study, there is the possibility of greatly underestimating the actual prevalence, because there are many reasons that patients with persistent symptoms might not visit the health-care service. It adds that although the number might be underestimated, SARS-CoV-2-positive individuals still more frequently developed dyspnoea than SARS-CoV-2-negative individuals, supporting the finding of greater prescription of bronchodilating agents in SARS-CoV-2-positive individuals. It notes that considering the possibility of an underestimate, the short follow-up time, and the huge numbers of SARS-CoV-2 infections worldwide, venous thromboembolism could be a potential concern. It concludes that most SARS-CoV-2 infections will remain asymptomatic and mild for the foreseeable future, so understanding the long-term consequences of COVID-19 in these populations is crucial to the natural history of the emerging disease.