School of Medicine, International University of Health and Welfare, Kozunomori 4-3, Narita City, Chiba, 286-8686, Japan.
Kyoto University School of Public Health, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
Theor Biol Med Model. 2021 Jul 17;18(1):13. doi: 10.1186/s12976-021-00146-x.
In Japan, a part of confirmed patients' samples have been screened for the variant of concern (VOC), including the variant alpha with N501Y mutation. The present study aimed to estimate the actual number of cases with variant alpha and reconstruct the epidemiological dynamics.
The number of cases with variant alpha out of all PCR confirmed cases was estimated, employing a hypergeometric distribution. An exponential growth model was fitted to the growth data of variant alpha cases over fourteen weeks in Tokyo.
The weekly incidence with variant alpha from 18-24 January 2021 was estimated at 4.2 (95% confidence interval (CI): 0.7, 44.0) cases. The expected incidence in early May ranged from 420-1120 cases per week, and the reproduction number of variant alpha was on the order of 1.5 even under the restriction of contact from January-March, 2021, Tokyo.
The variant alpha was predicted to swiftly dominate COVID-19 cases in Tokyo, and this has actually occurred by May 2021. Devising the proposed method, any country or location can interpret the virological sampling data.
在日本，已对部分确诊患者样本进行了变体关注（VOC）筛查，包括带有 N501Y 突变的变体 alpha。本研究旨在估计实际的变体 alpha 病例数并重建流行病学动态。
利用超几何分布估计所有 PCR 确诊病例中变体 alpha 的病例数。对东京 14 周内变体 alpha 病例的增长数据拟合指数增长模型。
2021 年 1 月 18 日至 24 日，变体 alpha 的每周发病率估计为 4.2（95%置信区间（CI）：0.7，44.0）例。预计 5 月初每周的病例数为 420-1120 例，即使在 2021 年 1 月至 3 月限制接触的情况下，变体 alpha 的繁殖数也在 1.5 左右。
预计变体 alpha 将迅速在东京主导 COVID-19 病例，而实际上到 2021 年 5 月已经发生了这种情况。通过提出的方法，任何国家或地区都可以解释病毒学采样数据。
