http://orcid.org/0000-0001-8710-5427
Reader Comments
Post a new comment on this article
Post Your Discussion Comment
Please follow our guidelines for comments and review our competing interests policy. Comments that do not conform to our guidelines will be promptly removed and the user account disabled. The following must be avoided:
- Remarks that could be interpreted as allegations of misconduct
- Unsupported assertions or statements
- Inflammatory or insulting language
Thank You!
Thank you for taking the time to flag this posting; we review flagged postings on a regular basis.
closeTime dependence in the transmission risk during the course of infection
Posted by gdrotos on 21 Dec 2020 at 10:10 GMT
I would like to point out an important aspect in the interpretation of the apparent event-to-event variability in the risk of transmission, which has gained epidemiological support since the publication of the paper by Koh et al. [1].
This aspect is the time dependence in the risk of transmission during the course of infection. In epidemiological settings, Sun et al. [2] and Ferretti et al. [3] found a peak in the transmission risk within a few-day interval around the time of symptom onset. This finding is in accordance with earlier studies of viral shedding [4-8]. Note also a study from Goyal et al. [9] according to which a high transmission risk may be concentrated to less than a day on the level of individuals. Such a situation may perhaps correspond to surprisingly high secondary attack rates at contact events with an appropriate timing (cf. the phenomenon of superspreading).
I believe that future studies should take care of the temporal profile of the transmission risk, because it may have important implications for containment measures, and modeling approaches may also need to take it into account. Note that simply distinguishing between pre-symptomatic and symptomatic phases may not be sufficient.
[1] Koh et al. What do we know about SARS-CoV-2 transmission? A systematic review and meta-analysis of the secondary attack rate and associated risk factors. PLOS ONE 2020;15(10):e0240205, https://doi.org/10.1371/j...
[2] Sun et al. Transmission heterogeneities, kinetics, and controllability of SARS-CoV-2. Science 2020;eabe2424, https://doi.org/10.1126/s...
[3] Ferretti et al. The Timing of COVID-19 Transmission. SSRN 2020, https://doi.org/10.2139/s...
[4] He et al. Temporal dynamics in viral shedding and transmissibility of COVID-19. Nat. Med. 2020;26:672-675, https://doi.org/10.1038/s...
[5] Wölfel et al. Virological assessment of hospitalized patients with COVID-2019. Nature 2020;581:465-469, https://doi.org/10.1038/s...
[6] To et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: An observational cohort study. Lancet Infect. Dis. 2020;20:565-574, https://doi.org/10.1016/S...(20)30196-1
[7] van Kampen et al. Shedding of infectious virus in hospitalized patients with coronavirus disease-2019 (COVID-19): duration and key determinants. medRxiv 2020, https://doi.org/10.1101/2...
[8] Singanayagam et al. Duration of infectiousness and correlation with RT-PCR cycle threshold values in cases of COVID-19, England, January to May 2020. Euro Surveill. 2020;25:2001483, https://doi.org/10.2807/1...
[9] Goyal et al. Wrong person, place and time: viral load and contact network structure predict SARS-CoV-2 transmission and super-spreading events. medRxiv 2020, https://doi.org/10.1101/2...