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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.

Background: Current mitigation strategies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rely on population-wide adoption of non-pharmaceutical interventions (NPIs). Collecting demographically and geographically resolved data on NPIs and their association with SARS-CoV-2 infection history can provide critical information related to reopening geographies. Methods: We sampled 1,030 individuals in Maryland from June 17 - June 28, 2020 to capture socio-demographically and geographically resolved information about NPI adoption, access to SARS-CoV-2 testing, and examine associations with self-reported SARS-CoV-2 positivity. Results: Median age of the sample was 43 years and 45% were men; Whites and Blacks/African Americans represented 60% and 23%, respectively. Overall, 96% of the sample reported traveling outside their home for non-employment related services: most commonly cited reasons were essential services (92%) and visiting friends/family (66%). Use of public transport was reported by 18% of respondents. 68% reported always social distancing indoors and 53% always wearing masks indoors; indoor social distancing was significantly less common among younger vs. older individuals, and race/ethnicity and income were significantly associated with mask use (p<0.05 for all). 55 participants (5.3%) self-reported ever testing positive for SARS-CoV-2 with strong dose-response relationships between movement frequency and SARS-CoV-2 positivity that were significantly attenuated by social distancing. In multivariable analysis, history of SARS-CoV-2 infection was negatively associated with the practice of social distancing (adjusted Odd Ratio [aOR]: 0.10; 95% Confidence Interval: 0.03 - 0.33); the only travel associated with higher likelihood of SARS-CoV-2 infection was use of public transport (aOR for 7 or more times vs. never: 4.29) and visiting a place of worship (aOR for 3 or more times vs. never: 16.0) after adjusting for social distancing. Conclusions: Using a rapid cost-efficient approach, we highlight the role of movement and social distancing on SARS-CoV-2 transmission risk. Continued monitoring of NPI uptake, access to testing, and the subsequent impact on SARS-CoV-2 transmission will be critical for pandemic control and decisions about reopening geographies.

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.

Background Monoclonal antibodies (mAbs) against SARS-CoV-2 are a promising treatment for limiting the progression of COVID-19 and decreasing strain on hospitals. Their use, however, remains limited, particularly in disadvantaged populations. Methods Electronic health records were reviewed from SARS-CoV-2 patients at a single medical center in the United States that initiated mAb infusions in January 2021 with the support of the U.S. Department of Health and Human Services’ National Disaster Medical System. Patients who received mAbs were compared to untreated patients from the time period before mAb availability who met eligibility criteria for mAb treatment. We used logistic regression to measure the effect of mAb treatment on the risk of hospitalization or emergency department (E.D.) visit within 30 days of laboratory-confirmed COVID-19. Results Of 598 COVID-19 patients, 270 (45%) received bamlanivimab and 328 (55%) were untreated. Two hundred and thirty-one patients (39%) were Hispanic. Among treated patients, 5/270 (1.9%) presented to the E.D. or required hospitalization within 30 days of a positive SARS-CoV-2 test, compared to 39/328 (12%) untreated patients (p&lt;0.001). After adjusting for age, gender, and comorbidities, the risk of E.D. visit or hospitalization was 82% lower in mAb-treated patients compared to untreated patients (95% confidence interval [CI]: 56%-94%). Conclusions In this diverse, real-world COVID-19 patient population, mAb treatment significantly decreased the risk of subsequent E.D. visit or hospitalization. Broader treatment with mAbs, including in disadvantaged patient populations, can decrease the burden on hospitals and should be facilitated in all populations in the United States to ensure health equity.

Background Current mitigation strategies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rely on population-wide adoption of non-pharmaceutical interventions (NPIs). Monitoring NPI adoption and their association with SARS-CoV-2 infection history can provide key information for public health. Methods We sampled 1,030 individuals in Maryland from June 17 – June 28, 2020 to capture socio-demographically and geographically resolved information about NPI adoption, access to SARS-CoV-2 testing, and examine associations with self-reported SARS-CoV-2 positivity. Results Overall, 92% reported traveling for essential services and 66% visited friends/family. Use of public transport was reported by 18%. In total, 68% reported strict social distancing indoors and 53% strict masking indoors; indoor social distancing was significantly associated with age, and race/ethnicity and income with masking. Overall, 55 participants (5.3%) self-reported ever testing positive for SARS-CoV-2 with strong dose-response relationships between several forms of movement frequency and SARS-CoV-2 positivity. In multivariable analysis, history of SARS-CoV-2 infection was negatively associated with strict social distancing (adjusted Odd Ratio for outdoor social distancing [aOR]: 0.10; 95% Confidence Interval: 0.03 – 0.33); only public transport use (aOR for ≥7 times vs. never: 4.29) and visiting a place of worship (aOR for ≥3 times vs. never: 16.0) remained significantly associated with SARS-CoV-2 infection after adjusting for strict social distancing and demographics. Conclusions These results support public health messaging that strict social distancing during most activities can reduce SARS-CoV-2 transmission. Additional considerations are needed for indoor activities with large numbers of persons (places of worship and public transportation) where even NPIs may not be possible or sufficient.

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.

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