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. 2020 Sep 17:M20-5008. doi: 10.7326/M20-5008

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This article is made available via the PMC Open Access Subset for unrestricted re-use for research, analyses, and text and data mining through PubMed Central. Acknowledgement of the original source shall include a notice similar to the following: "© 2020 American College of Physicians. Some rights reserved. This work permits non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited." These permissions are granted for the duration of the COVID-19 pandemic or until permissions are revoked in writing. Upon expiration of these permissions, PMC is granted a perpetual license to make this article available via PMC and Europe PMC, consistent with existing copyright protections.

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Figure 1. The period of infectiousness for immunocompetent, symptomatic adults (dotted line) and respiratory tract viral load with time (solid line). The vertical dashed line represents symptom onset. — The vertical dashed line represents symptom onset.