Prevalence and factors associated with symptom persistence: A prospective study of 429 mild COVID-19 outpatients

Persistent symptoms have recently emerged as a clinical issue in COVID-19. We aimed to assess the prevalence and risk factors in symptomatic non-hospitalized individuals with mild COVID-19.

We performed a prospective cohort study of symptomatic COVID-19 outpatients, from March to May 2020, with weekly phone calls from clinical onset until day 30 and up to day 60 in case of persistent symptoms. The main outcomes were the proportion of patients with complete recovery at day 30 and day 60 and factors associated with persistent symptoms.

We enrolled 429 individuals mostly women (72.5%) and healthcare workers (72.5%), with a median age of 41.6 years [IQR 30-51.5]. Symptoms included: cough (69.7%), asthenia (68.8%), anosmia (64.8%), headaches (64.6%), myalgia (62.7%), gastrointestinal symptoms (61.8%), fever (61.5%), and ageusia (60.8%). Mean duration of disease was 27 days (95%CI: 25-29). The rate of persistent symptoms was 46.8% at day 30 and 6.5% at day 60 consisting in asthenia (32.6%), anosmia (32.6%), and ageusia (30.4%). The probability of complete recovery was 56.3% (95%CI: 51.7-61.1) at day 30 and 85.6% (95%CI: 81.2-89.4) at day 60. Factors associated with persistent symptoms were age>40 (HR 0.61), female sex (HR 0.70), low cycle threshold (HR 0.78), and ageusia (HR 0.59).

COVID-19 - even in its mild presentation - led to persistent symptoms (up to one month) in nearly half of individuals. Identification of risk factors such as age, gender, ageusia and viral load is crucial for clinical management and argues for the development of antiviral agents.