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. 2020 Oct:99:403-407.
doi: 10.1016/j.ijid.2020.07.075. Epub 2020 Aug 6.

Transmission onset distribution of COVID-19

June Young Chun  1 , Gyuseung Baek  2 , Yongdai Kim  3
Affiliations

Transmission onset distribution of COVID-19

June Young Chun et al. Int J Infect Dis. 2020 Oct.

Erratum in

Abstract

Objectives: The distribution of the transmission onset of COVID-19 relative to the symptom onset is a key parameter for infection control. It is often not easy to study the transmission onset time, as it is difficult to know who infected whom exactly when.

Methods: We inferred transmission onset time from 72 infector-infectee pairs in South Korea, either with known or inferred contact dates, utilizing the incubation period. Combining this data with known information of the infector's symptom onset, we could generate the transmission onset distribution of COVID-19, using Bayesian methods. Serial interval distribution could be automatically estimated from our data.

Results: We estimated the median transmission onset to be 1.31 days (standard deviation, 2.64 days) after symptom onset with a peak at 0.72 days before symptom onset. The pre-symptomatic transmission proportion was 37% (95% credible interval [CI], 16-52%). The median incubation period was estimated to be 2.87 days (95% CI, 2.33-3.50 days), and the median serial interval to be 3.56 days (95% CI, 2.72-4.44 days).

Conclusions: Considering that the transmission onset distribution peaked with the symptom onset and the pre-symptomatic transmission proportion is substantial, the usual preventive measures might be too late to prevent SARS-CoV-2 transmission.

Keywords: COVID-19; Infectious disease incubation period; Infectious disease transmission; SARS-CoV-2.

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Figures

Figure 1
Figure 1
Transmission plot of infector-infectee pairs. For cases of continuous exposure, the interval presentation was limited to 10 days before the symptom onset, whoever came first. The upper 95th percentile of the pre-estimated incubation period is 10.1.
Figure 2
Figure 2
The number of secondary infections per infector in the reported data set.
Figure 3
Figure 3
Estimated distribution W of the transmission onset of COVID-19 relative to the symptom onset (A) using the incubation period distribution in the current study, and (B) using the previous incubation period distribution (Lauer et al., 2020).
See this image and copyright information in PMC

References

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