Mild COVID-19 Is Not Necessarily Benign

Substantial numbers of patients hospitalized with COVID-19 have lingering symptoms several months after discharge. What happens after mild disease? Researchers in Sweden invited healthcare professionals with mild COVID-19 (age range, 33–56; 85% women) to complete baseline questionnaires and have blood samples tested every 4 months for SARS-CoV-2 anti-spike IgG. At the 8-month follow up, 323 seropositive and 1072 seronegative participants reported on persistence, severity, and duration of 23 predefined symptoms. Underlying chronic conditions were reported by 23% of participants regardless of serostatus.

At least 1 moderate-to-severe symptom lasting ≥2 months was reported by 26% (seropositive) versus 9% (seronegative) participants; symptoms la…