Temporal dynamics in viral shedding and transmissibility of COVID-19

He, Xiaoyun; Lau, Eric H Y; Wu, Peng; Deng, Xilong; Wang, Jian; Hao, Xinxin; Lau, Yiu Chung; Wong, Jessica Y.; Guan, Yubao; Tan, Xinghua; Mo, Xiaoneng; Chen, Yanqing; Liao, Baolin; Chen, Weilie; Hu, Fengyu; Zhang, Qing; Zhong, Mingqiu; Wu, Yanrong; Zhao, Liang; Zhang, Fuchun; Cowling, Benjamin J.; Li, Fang; Leung, Gabriel M.

doi:10.1101/2020.03.15.20036707

Cited by 1,221 publications

(1,810 citation statements)

References 19 publications

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“…Many of the studies cited here (& others -e.g. [18] ) have more longitudinal data from more patients but which is not currently publicly available, or not disaggregated by swab type. Inclusion of this data would provide superior estimates, in particular if it is disaggregated into tests done from different samples via different routes in the same patient.…”

Section: Limitationsmentioning

confidence: 99%

Estimating false-negative detection rate of SARS-CoV-2 by RT-PCR

Wikramaratna

Paton

Ghafari

2020

Preprint

150

166

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Reverse transcription-polymerase chain reaction (RT-PCR) assays are used to test patients and key workers for infection with the causative SARS-CoV-2 virus. RT-PCR tests are highly specific and the probability of false positives is low, but false negatives can occur if the sample contains insufficient quantities of the virus to be successfully amplified and detected. The amount of virus in a swab is likely to vary between patients, sample location (nasal, throat or sputum) and through time as infection progresses. Here, we analyse publicly available data from patients who received multiple RT-PCR tests and were identified as SARS-CoV-2 positive at least once. We identify that the probability of a positive test decreases with time after symptom onset, with throat samples less likely to yield a positive result relative to nasal samples. Empirically derived distributions of the time between symptom onset and hospitalisation allowed us to comment on the likely false negative rates in cohorts of patients who present for testing at different clinical stages. We further estimate the expected numbers of false negative tests in a group of tested individuals and show how this is affected by the timing of the tests. Finally, we assessed the robustness of these estimates of false negative rates to the probability of false positive tests. This work has implications both for the identification of infected patients and for the discharge of convalescing patients who are potentially still infectious.

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Section: Limitationsmentioning

confidence: 99%

Estimating false-negative detection rate of SARS-CoV-2 by RT-PCR

Wikramaratna

Paton

Ghafari

2020

Preprint

150

166

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“…A proper work-lockdown cycle, such as a 4-work:10-lockdown schedule, allows most of those infected during work days to reach maximal infectiousness during lockdown, and thus avoid infecting many others. Those with symptoms can be infectious for longer ( 9 ) , but can be detected by their symptoms and remain (self-)quarantined along with their household members, preventing secondary infections outside the household. Similarly, asymptomatic cases infected at work will spend the majority of their peak infectious period under lockdown.…”

Section: Fig 2 | Staggered Cyclic Work-lockdown Strategy In Which Thmentioning

confidence: 99%

Cyclic exit strategies to suppress COVID-19 and allow economic activity

Karin

Bar-On

Milo

et al. 2020

Preprint

119

157

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Many countries have applied lockdown that helped suppress COVID-19, but with devastating economic consequences. Here we propose exit strategies from lockdown that provide sustainable, albeit reduced, economic activity. We use mathematical models to show that a cyclic schedule of 4-day work and 10-day lockdown, or similar variants, can, in certain conditions, suppress the epidemic while providing part-time employment. The cycle reduces the reproduction number R by a combination of reduced exposure time and an anti-phasing effect in which those infected during work days reach peak infectiousness during lockdown days. The number of work days can be adapted in response to observations. Throughout, full epidemiological measures need to continue including hygiene, physical distancing, compartmentalization and extensive testing and contact tracing. We do not call for immediate adoption of this policy, but rather to consider it as a conceptual framework, which, when combined with other interventions to control the epidemic, can offer the beginnings of predictability to many economic sectors.Current non-pharmaceutical interventions (NPI) to suppress COVID-19 use testing, contact tracing, physical distancing, mask use, identification of regional outbreaks, compartmentalization down to the neighborhood and company level, and population-level quarantine at home known as lockdown ( 1 -4 ) . The aim is to flatten the infection curve and prevent overload of the medical system until a vaccine becomes available.Lockdown is currently in place in many countries. It has a large economic and social cost, including unemployment on a massive scale. Once a lockdown has reduced the number of critical cases to a desired goal, a decision must be reached on how to exit it responsibly. The main concern is the risk of resurgence of the epidemic. One strategy proposes reinstating lockdown when a threshold number of critical cases is exceeded in a resurgence, and stopping lockdown again once cases drop below a low threshold ( 2 , 5 ) ( Fig 1A,S1). While such an "adaptive triggering" strategy can prevent healthcare services from becoming overloaded, it leads to economic uncertainty and continues to accumulate cases with each resurgence.

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“…[5] Transmission of the SARS-CoV-2 virus from these patients is common because viral shedding begins before the onset of symptoms. [6][7][8] The airway of infected patients has been shown to have a high viral load, especially in the nose, throat and trachea. [9] Otolaryngologists, oral surgeons, dentists, ophthalmologists, and anesthesiologists are among those at highest risk for infection, given the procedures they perform in or near the upper aerodigestive tract.…”

Section: Introductionmentioning

confidence: 99%

Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: A four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes

Francom

Javia

Wolter

et al. 2020

International Journal of Pediatric Otorhinolaryngology

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bronchoscopy during the COVID-19 pandemic: A four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes, International Journal of Pediatric Otorhinolaryngology, https://doi.are co-senior authors Running Title: Bronchoscopy during the COVID-19 pandemic.Word Count: 3671 words. Abstract:Aerosolization procedures during the COVID-19 pandemic place all operating room personnel at risk for exposure. We offer detailed perioperative management strategies and present a specific protocol designed to improve safety during pediatric laryngoscopy and bronchoscopy. Several methods of using disposable drapes for various procedures are described, with the goal of constructing a tent around the patient to decrease widespread contamination of dispersed droplets and generated aerosol. The concepts presented herein are translatable to future situations where aerosol generating procedures increase risk for any pathogenic exposure. This protocol is a collaborative effort based on knowledge gleaned from clinical and simulation experience from Children's Hospital Colorado, Children's Hospital of Philadelphia, The Hospital for Sick Children in Toronto, and Boston Children's Hospital.

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Temporal dynamics in viral shedding and transmissibility of COVID-19

Cited by 1,221 publications

References 19 publications

Estimating false-negative detection rate of SARS-CoV-2 by RT-PCR

Estimating false-negative detection rate of SARS-CoV-2 by RT-PCR

Cyclic exit strategies to suppress COVID-19 and allow economic activity

Pediatric laryngoscopy and bronchoscopy during the COVID-19 pandemic: A four-center collaborative protocol to improve safety with perioperative management strategies and creation of a surgical tent with disposable drapes

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