ABSTRACT
BackgroundOver-the-counter rapid antigen tests for SARS-CoV-2 with an Emergency Use Authorization (EUA) in the United States generally include a condition of authorization to evaluate the tests performance in asymptomatic individuals when used serially. A goal of this study was to investigate the performance of SARS-CoV-2 antigen serial testing and generate data to support regulatory decisions. ObjectiveTo describe a novel study design to evaluate serial use of rapid antigen tests in detecting SARS-CoV-2 virus among asymptomatic individuals. DesignProspective cohort study using a decentralized approach. Eligible participants from across the U.S. could enroll and complete this study from their home environment through a study app. Participant enrollment was prioritized based on regional 7-day case rates, participants vaccination status, and sociodemographic characteristics prior to enrollment. Prioritization criteria were adjusted on a daily or weekly basis. Enrolled participants were mailed rapid antigen tests and molecular comparator collection kits and asked to test every 48 hours for 15 days. Three companies rapid antigen tests were used in the study; assignment of participant to a test was criteria-based and non-random, precluding head-to-head comparison between the tests. ParticipantsMainland United States residents over 2 years old with no reported COVID-19 symptoms in the 14 days prior to study enrollment. Main MeasuresParticipant demographics, COVID-19 vaccination status, and geographic distribution were used to understand the impact of the site-less recruitment and enrollment strategy. Key ResultsA total of 7,361 participants enrolled in the study between October 18, 2021 and February 15, 2022. Throughout the study, 369 participants tested positive for SARS-CoV-2, including 167 who were asymptomatic and tested negative on SARS-CoV-2 molecular assays to start the study. This exceeded the initial enrollment goals of 60 positive participants. We enrolled participants from 44 of the 48 mainland U.S. states, and geographic distribution of participants shifted in accordance with the changing COVID-19 prevalence nationwide. ConclusionsThe novel, digital site-less approach employed in the Test Us At Home study enabled rapid, efficient, and rigorous evaluation of rapid diagnostics for COVID-19, and can be adapted across research disciplines to optimize study enrollment and accessibility.
ABSTRACT
ImportanceWide-spread distribution of diagnostics is an integral part of the United States COVID-19 strategy; however, few studies have assessed the effectiveness of this intervention at reducing transmission of community COVID-19. ObjectiveTo assess the impact of the Say Yes! Covid Test (SYCT!) Michigan program, a population-based program that distributed 20,000 free rapid antigen tests within Ann Arbor and Ypsilanti, Michigan in June-August 2021, on community prevalence of SARS-CoV-2. DesignThis ecological study analyzed cases of SARS-CoV-2 from March to October 2021 reported to the Washtenaw County Health Department. SettingWashtenaw County, Michigan ParticipantsAll residents of Washtenaw County InterventionsCommunity-wide distribution of 500,000 rapid antigen tests for SARS-CoV-2 to residents of Ann Arbor and Ypsilanti, Michigan. Each household was limited to one test kit containing 25 rapid antigen tests. Main Outcome and MeasuresCommunity prevalence of SARS-CoV-2, as measured through 7-day average cases, in Ann Arbor and Ypsilanti was compared to the rest of Washtenaw County. A generalized additive model was fitted with non-parametric trends for control and relative differences of trends in the pre-intervention, intervention, and post-intervention periods to compare intervention municipalities of Ann Arbor and Ypsilanti to the rest of Washtenaw County. Model results were used to calculate average cases prevented in the post-intervention period. ResultsIn the post-intervention period, there were significantly lower standardized average cases in the intervention communities of Ann Arbor/Ypsilanti compared to the rest of Washtenaw County (p<0.001). The estimated standardized relative difference between Ann Arbor/Ypsilanti and the rest of Washtenaw County was -0.016 cases per day (95% CI: -0.020 to -0.013), implying that the intervention prevented 40 average cases per day two months into the post-intervention period if trends were consistent. Conclusions and RelevanceMass distribution of rapid antigen tests may be a useful mitigation strategy to combat community transmission of SARS-CoV-2, especially given the recent relaxation of social distancing and masking requirements.
ABSTRACT
ImportanceWide-spread distribution of rapid-antigen tests is integral to the United States strategy to address COVID-19; however, it is estimated that few rapid-antigen test results are reported to local departments of health. ObjectiveTo characterize how often individuals in six communities throughout the United States used a digital assistant to log rapid-antigen test results and report them to their local Department of Health. DesignThis prospective cohort study is based on anonymously collected data from the beneficiaries of The Say Yes! Covid Test program, which distributed 3,000,000 rapid antigen tests at no cost to residents of six communities between April and October 2021. We provide a descriptive evaluation of beneficiaries use of digital assistant for logging and reporting their rapid antigen test results. Main Outcome and MeasuresNumber and proportion of tests logged and reported to the Department of Health through the digital assistant ResultsA total of 178,785 test kits were ordered by the digital assistant, and 14,398 households used the digital assistant to log 41,465 test results. Overall, a small proportion of beneficiaries used the digital assistant (8%), but over 75% of those who used it reported their rapid antigen test results to their state public health department. The reporting behavior varied between communities and was significantly different for communities that were incentivized for reporting test results (p < 0.001). In all communities, positive tests were less reported than negative tests (60.4% vs 75.5%; p<0.001). Conclusions and RelevanceThese results indicate that app-based reporting with incentives may be an effective way to increase reporting of rapid tests for COVID-19; however, increasing the adoption of the digital assistant is a critical first step.
ABSTRACT
BackgroundThe goal of this study was to characterize the ability of school-aged children to self-collect adequate anterior nares (AN) swabs for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing. MethodsFrom July to August 2021, 287 children, age 4-14 years-old, were prospectively enrolled in the Atlanta area. Symptomatic (n=197) and asymptomatic (n=90) children watched a short instructional video before providing a self-collected AN specimen. Health care workers (HCWs) then collected a second specimen, and useability was assessed by the child and HCW. Swabs were tested side-by-side for SARS-CoV-2. RNase P RNA detection was investigated as a measure of specimen adequacy. ResultsAmong symptomatic children, 87/196 (44.4%) tested positive for SARS-CoV-2 by both self- and HCW-swab. Two children each were positive by self- or HCW-swab; one child had an invalid HCW-swab. Compared to HCW-swabs, self-collected swabs had 97.8% and 98.1% positive and negative percent agreements, respectively, and SARS-CoV-2 Ct values did not differ significantly between groups. Participants [≤]8 years-old were less likely than those >8 to be rated as correctly completing self-collection, but SARS-CoV-2 detection did not differ. Based on RNase P RNA detection, 270/287 children (94.1%) provided adequate self-swabs versus 277/287 (96.5%) HCW-swabs (p=0.24) with no difference when stratified by age. ConclusionsChildren, aged 4-14 years-old, can provide adequate AN specimens for SARS-CoV-2 detection when presented with age-appropriate instructional material, consisting of a video and a handout, at a single timepoint. These data support the use of self-collected AN swabs among school-age children for SARS-CoV-2 testing.
ABSTRACT
The dynamics of SARS-CoV-2 replication and shedding in humans remain poorly understood. We captured the dynamics of infectious virus and viral RNA shedding during acute infection through daily longitudinal sampling of 60 individuals for up to 14 days. By fitting mechanistic models, we directly estimate viral reproduction and clearance rates, and overall infectiousness for each individual. Significant person-to-person variation in infectious virus shedding suggests that individual-level heterogeneity in viral dynamics contributes to superspreading. Viral genome load often peaked days earlier in saliva than in nasal swabs, indicating strong compartmentalization and suggesting that saliva may serve as a superior sampling site for early detection of infection. Viral loads and clearance kinetics of B.1.1.7 and non-B.1.1.7 viruses in nasal swabs were indistinguishable, however B.1.1.7 exhibited a significantly slower pre-peak growth rate in saliva. These results provide a high-resolution portrait of SARS-CoV-2 infection dynamics and implicate individual-level heterogeneity in infectiousness in superspreading.
