The transmissibility of novel Coronavirus in the early stages of the 2019-20 outbreak in Wuhan: Exploring initial point-source exposure sizes and durations using scenario analysis.
The transmissibility of novel Coronavirus in the early stages of the 2019-20 outbreak in Wuhan: Exploring initial point-source exposure sizes and durations using scenario analysis.
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DOI：
10.12688/wellcomeopenres.15718.1
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发表时间：
2020-01-01
影响因子：
--
通讯作者：
Funk, Sebastian
中科院分区：
文献类型：
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作者：
Abbott, Sam;Hellewell, Joel;Funk, Sebastian
背景资料：目前的新型冠状病毒疫情似乎起源于中国武汉华南海鲜批发市场的点源暴露事件。关于这次暴露事件的规模和持续时间仍然存在不确定性。这对冠状病毒的估计传播能力产生了影响，因此，应该探讨这些潜在的情况。 研究方法：我们使用了一个随机分支过程模型，在可能的情况下，以可用数据为参数，并以2002-2003年严重急性呼吸系统综合征（SARS）爆发为信息，来模拟武汉疫情。我们评估了以下参数的场景：初始传输事件的大小和持续时间，串行间隔和再现次数（R 0）。我们根据1月25日观察到的案例数量限制了模型模拟，接受在此估计值两侧5%区间内的样本。结果：使用干预前SARS样系列间隔提示较大的初始传播事件和较高的R 0估计。使用类似SARS的序列区间，我们发现最有可能的情况下产生的R 0估计值在2-2.7之间（90%可信区间（CrI））。干预前SARS样系列间期导致R 0估计值在2-3之间（90% CrI）。还有其他合理的情景，事件规模较小，持续时间较长，具有可比的R 0估计值。当R 0小于1时，很少有模拟能够再现观测数据。结论：我们的研究结果表明，R 0小于1是极不可能的，除非初始暴露事件的规模远大于目前报道的。我们发现，R 0估计值在事件规模减小和持续时间增加的情况下具有可比性。具有干预前SARS样连续间期的情景导致更高的R 0，并且与具有SARS样连续间期的情景同样合理。
Background: The current novel coronavirus outbreak appears to have originated from a point-source exposure event at Huanan seafood wholesale market in Wuhan, China. There is still uncertainty around the scale and duration of this exposure event. This has implications for the estimated transmissibility of the coronavirus and as such, these potential scenarios should be explored. Methods: We used a stochastic branching process model, parameterised with available data where possible and otherwise informed by the 2002-2003 Severe Acute Respiratory Syndrome (SARS) outbreak, to simulate the Wuhan outbreak. We evaluated scenarios for the following parameters: the size, and duration of the initial transmission event, the serial interval, and the reproduction number (R0). We restricted model simulations based on the number of observed cases on the 25th of January, accepting samples that were within a 5% interval on either side of this estimate. Results: Using a pre-intervention SARS-like serial interval suggested a larger initial transmission event and a higher R0 estimate. Using a SARs-like serial interval we found that the most likely scenario produced an R0 estimate between 2-2.7 (90% credible interval (CrI)). A pre-intervention SARS-like serial interval resulted in an R0 estimate between 2-3 (90% CrI). There were other plausible scenarios with smaller events sizes and longer duration that had comparable R0 estimates. There were very few simulations that were able to reproduce the observed data when R0 was less than 1. Conclusions: Our results indicate that an R0 of less than 1 was highly unlikely unless the size of the initial exposure event was much greater than currently reported. We found that R0 estimates were comparable across scenarios with decreasing event size and increasing duration. Scenarios with a pre-intervention SARS-like serial interval resulted in a higher R0 and were equally plausible to scenarios with SARs-like serial intervals.