JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China.
CUHK Shenzhen Research Institute, Shenzhen, China.
J Glob Health. 2021 Dec 25;11:05028. doi: 10.7189/jogh.11.05028. eCollection 2021.
The COVID-19 pandemic poses serious threats to public health globally, and the emerging mutations in SARS-CoV-2 genomes has become one of the major challenges of disease control. In the second epidemic wave in Nigeria, the roles of co-circulating SARS-CoV-2 Alpha (ie, B.1.1.7) and Eta (ie, B.1.525) variants in contributing to the epidemiological outcomes were of public health concerns for investigation.
We developed a mathematical model to capture the transmission dynamics of different types of strains in Nigeria. By fitting to the national-wide COVID-19 surveillance data, the transmission advantages of SARS-CoV-2 variants were estimated by likelihood-based inference framework.
The reproduction numbers were estimated to decrease steadily from 1.5 to 0.8 in the second epidemic wave. In December 2020, when both Alpha and Eta variants were at low prevalent levels, their transmission advantages (against the wild type) were estimated at 1.51 (95% credible intervals (CrI) = 1.48, 1.54), and 1.56 (95% CrI = 1.54, 1.59), respectively. In January 2021, when the original variants almost vanished, we estimated a weak but significant transmission advantage of Eta against Alpha variants with 1.14 (95% CrI = 1.11, 1.16).
Our findings suggested evidence of the transmission advantages for both Alpha and Eta variants, of which Eta appeared slightly more infectious than Alpha. We highlighted the critical importance of COVID-19 control measures in mitigating the outbreak size and relaxing the burdens to health care systems in Nigeria.
COVID-19 大流行对全球公共卫生构成严重威胁，而 SARS-CoV-2 基因组中的新兴突变已成为疾病控制的主要挑战之一。在尼日利亚的第二波疫情中，循环的 SARS-CoV-2 Alpha（即 B.1.1.7）和 Eta（即 B.1.525）变体在导致流行病学结果方面的作用引起了公众的关注。
我们开发了一个数学模型来捕捉尼日利亚不同类型菌株的传播动态。通过拟合全国范围的 COVID-19 监测数据，通过基于似然的推断框架估计 SARS-CoV-2 变体的传播优势。
第二波疫情中，繁殖数从 1.5 稳步下降到 0.8。2020 年 12 月，当 Alpha 和 Eta 变体的流行率都较低时，它们相对于野生型的传播优势估计分别为 1.51（95%可信区间（CrI）= 1.48, 1.54）和 1.56（95% CrI = 1.54, 1.59）。2021 年 1 月，当原始变体几乎消失时，我们估计 Eta 变体对 Alpha 变体的传播优势较弱但具有统计学意义，为 1.14（95% CrI = 1.11, 1.16）。
我们的研究结果表明，Alpha 和 Eta 变体都具有传播优势，其中 Eta 比 Alpha 变体略具传染性。我们强调了 COVID-19 控制措施在减轻尼日利亚疫情规模和减轻医疗保健系统负担方面的重要性。
