Background Outpatient COVID-19 has been insufficiently characterized. To determine the progression of disease and determinants of hospitalization, we conducted a prospective cohort study. Methods Outpatient adults with positive RT-PCR results for SARS-CoV-2 were recruited by phone between April 21 to July 23, 2020 after receiving outpatient or emergency department testing within a large health network in Maryland, USA. Symptoms were collected by participants on days 0, 3, 7, 14, 21, and 28 and portable pulse oximeter oxygen saturation (SaO2), heart rate, and temperature were collected for 15 consecutive days. Baseline demographics, comorbid conditions, and vital signs were evaluated for risk of subsequent hospitalization using negative binomial, and logistic regression. Results Among 118 SARS-CoV-2 infected outpatients, the median age was 56.0 years (IQR, 50.0 to 63.0) and 50 (42.4%) were male. Among individuals in the first week of illness (N=61), the most common symptoms included weakness/fatigue (65.7%), cough (58.8%), headache (45.6%), chills (38.2%), and anosmia (27.9%). Participants returned to their usual health a median of 20 days (IQR, 13 to 38) from symptom onset, and 66.0% of respondents were at their usual health during the fourth week of illness. Over 28 days, 10.9% presented to the emergency department and 7.6% required hospitalization. The area under the receiving operating characteristic curve for the initial home SaO2 for predicting subsequent hospitalization was 0.86 (CI, 0.73 to 0.99). Conclusions Symptoms often persisted but uncommonly progressed to hospitalization among outpatients with COVID-19. Home SaO2 may be a helpful tool to stratify risk of hospitalization.

SARS-CoV-2 pandemic control will require widespread access to accurate diagnostics. Salivary sampling circumvents swab supply chain bottlenecks, is amenable to self-collection, and is less likely to create an aerosol during collection compared to the nasopharyngeal swab. We compared rRT-PCR Abbott m2000 results from matched salivary oral fluid (gingival crevicular fluid collected in an Oracol device) and nasal-oropharyngeal (OP) self-collected specimens in viral transport media from a non-hospitalized, ambulatory cohort of COVID-19 patients at multiple time points. There were 171 matched specimen pairs. Compared to nasal-OP swabs, 41.6% of the oral fluid samples were positive. Adding spit to the oral fluid collection device increased the percent positive agreement from 37.2% (16/43) to 44.6% (29/65). The percent positive agreement was highest in the first 5 days after symptoms and decreased thereafter. All of the infectious nasal-OP samples (culture positive on VeroE6 TMPRSS2 cells) had a matched SARS-CoV-2 positive oral fluid sample. In this study of non-hospitalized SARS-CoV-2 infected persons, we demonstrate lower diagnostic sensitivity of self-collected oral fluid compared to nasal-OP specimens, a difference that was especially prominent more than 5 days from symptom onset. These data do not justify the routine use of oral fluid collection for diagnosis of SARS-CoV-2 despite the greater ease of collection. It also underscores the importance of considering the method of saliva specimen collection, and the time from symptom onset especially in outpatient populations.

In an outpatient cohort in Maryland, clustering of SARS-CoV-2 positivity within households was high, with 76% of 74 households reporting at least one other symptomatic person and 66% reporting another person who tested SARS-CoV-2 positive. SARS-CoV-2 positivity among household members was associated with larger household size and bedroom sharing.

No abstract