Evaluation of the role of home rapid antigen testing to determine isolation period after infection with SARS-CoV-2
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Abstract
Importance
Recent CDC COVID-19 isolation guidance for non-immunocompromised individuals with asymptomatic or mild infection allows ending isolation after 5 days if asymptomatic or afebrile with improving symptoms. The role of rapid antigen testing in further characterizing the risk of viral transmission to others is unclear.
Objective
Understand rates of rapid antigen test (RAT) positivity after day 5 from a positive COVID-19 test and the relationship of this result to symptoms and viral culture.
Design
In this single center, observational cohort study, ambulatory individuals newly testing SARS-CoV-2 positive completed daily symptom logs, and RAT self-testing starting day 6 until negative. Anterior nasal and oral swabs were collected on a subset for viral culture.
Main Outcomes and Measures
Day 6 SARS-CoV-2 RAT result, symptoms and viral culture.
Results
40 individuals enrolled between January 5 and February 11, 2022 with a mean age of 32 years (range 22 to 57). 23 (58%) were women and 17 (42%) men. All were vaccinated. 33 (83%) were symptomatic. Ten (25%) tested RAT negative on day 6. 61 of 90 (68%) RATs performed on asymptomatic individuals after day 5 were positive. Day 6 viral cultures were positive in 6 (35%) of 17 individuals. A negative RAT or being asymptomatic on day 6 were 100% and 78% predictive respectively for negative culture, while improving symptoms was 69% predictive. A positive RAT was 50% predictive of positive culture.
Conclusion and Relevance
RATs are suboptimal in predicting viral culture results on day 6. Use of routine RATs to guide end of COVID-19 isolation could result in significant numbers of culture negative, potentially non-infectious individuals undergoing prolonged isolation. However, a negative RAT was highly predictive of being culture negative. Complete absence of symptoms was inferior to a negative RAT in predicting a negative culture result, but performed better than improving symptoms. If a positive viral culture is a proxy for infectiousness, these data may help further refine a safer strategy for ending isolation.
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SciScore for 10.1101/2022.03.03.22271766: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: Human Subjects: The research was reviewed and approved by the Mass General Brigham Institutional review board and by the Research Subjects Protection group at the Broad Institute.
Consent: All enrolled individuals provided online written informed consent.Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Viral culture was performed using Caco2 cells engineered to co-express Ace2 and TMPRSS2 which robustly support SARS-CoV-2 replication19–21. Caco2suggested: NoneResults from OddPub: We did not detect open data. We also did …
SciScore for 10.1101/2022.03.03.22271766: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: Human Subjects: The research was reviewed and approved by the Mass General Brigham Institutional review board and by the Research Subjects Protection group at the Broad Institute.
Consent: All enrolled individuals provided online written informed consent.Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
Experimental Models: Cell Lines Sentences Resources Viral culture was performed using Caco2 cells engineered to co-express Ace2 and TMPRSS2 which robustly support SARS-CoV-2 replication19–21. Caco2suggested: NoneResults from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:We acknowledge several limitations in this study, foremost is that it represents a relatively small cohort of young, vaccinated individuals with mild disease and presumed Omicron infection. These results would presumably vary in individuals who were older, unvaccinated or carried other co-morbidities, especially immunosuppression. The varying viral dynamics of the different variants would also inevitably affect the results of such a study. Additionally, the results are a function of the performance of self-collection and the technical assays used, including the specific RAT and its interpretation, and the method of culture. We intentionally used the Flowflex™ lateral flow RAT because it is FDA EUA approved for use in asymptomatic individuals. In addition, though RAT performance is in some studies less accurate in detection of the Omicron variant, the Flowflex™ has been shown to detect Omicron with reasonable sensitivity23. Similarly, while the decreased ability to culture Omicron has been reported24 our culture assay system utilizing Caco2 cells overexpressing Ace2 and TMPRSS2 has good sensitivity for culturing SARS-CoV-2 variants including Omicron,19,21 (JHC, unpublished data). Finally, and perhaps most significantly, both rapid antigen testing and culture are only proxies for transmission and correlates, not determinant, of infectiousness and transmissibility in vivo. While the degree to which viral culture completely and accurately reflects transmissibility remains an open...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
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