Onset, duration and unresolved symptoms, including smell and taste changes, in mild COVID-19 infections. A cohort study in Israeli patients

Abstract Objectives This study aims to characterize longitudinal symptoms of mild COVID-19 patients for a period of six months, and potentially aid in disease management. Methods Phone interviews were conducted with 103 mild COVID-19 patients in Israel, over a six-month period (April 2020 to October 2020). Patients were recruited via social media and word to mouth and were interviewed up to 4 times, depending on their unresolved symptoms reports. Inclusion criteria required participants to be Israeli residents aged ≥18 years, with positive COVID-19 RT-PCR results and non-severe symptoms. Symptoms' onset, duration, severity, and resolution were analyzed. Results 44% (45/103), 41% (42/103), 39% (40/103) or 38% (39/103) of the patients experienced headache, fever, muscle ache, or dry cough as the first symptom respectively. Smell and taste changes were experienced 3.9 ± 5.4 and 4.6 ± 5.7 days (mean ± SD) after disease onset, respectively. Among prevalent symptoms, fever had the shortest duration (5.8 ± 8.6 days), and taste and smell changes were the longest-lasting symptoms (17.2 ± 17.6 and 18.9 ± 19.7 days, durations censored at 60 days). Longer recovery of the sense of smell correlated with the extent of smell change. At the six-month follow-up, 46% (47/103) of the patients had at least one unresolved symptom, most commonly fatigue (22%, 23/103), smell and taste changes (15%, 15/103 and 8%, 8/103 respectively), and breathing difficulties (8%, 8/103). Conclusions Long-lasting effects of mild COVID-19 manifested in almost half of the participants reporting at least one unresolved symptom after six months.