Yadav Arun Kumar, Kumar Surinder, Singh Gurpreet, Kansara Nikunj Kumar
Department of Community Medicine, Armed Forces Medical College, Pune, Maharashtra, India.
PhD Scholar, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
Indian J Community Med. 2021 Jan-Mar;46(1):7-14. doi: 10.4103/ijcm.IJCM_989_20. Epub 2021 Mar 1.
Since the onset of the pandemic in Wuhan city, China, forecasting and projections of the pandemic are the areas of interest for the investigators, and the basic reproduction rate R0 always stayed the favorite tool. The basic reproduction number (R0) is either ratio or rate or the basic reproductive rate. This dimensionless number was calculated in the past to describe the contagiousness or transmissibility of infectious agents for many communicable diseases. Its importance in the context of COVID-19 is not less, it tells us about the public health measures to be undertaken for disease prevention, and how the transmission of COVID-19 will be affected or eliminated. R0 is affected by several biological, sociobehavioral, and environmental factors which decide agent transmission. R0 is estimated by using complex mathematical models, the results of which are easily distorted, misjudged, and misused. R0 is not a biological constant for an agent or pathogen, it is a rate over time. It can measure the disease severity and also gives an estimate about the herd immunity required for the reversal of epidemic. R0 cannot be altered through vaccination campaigns though it can tell us about the relationship between the population's immune status and epidemic curve. Modeled R0 values are dependent on the model structures and assumptions made. Some R0 values reported in the scientific literature are likely outdated as assumptions are frequently changing in the current pandemic. R0 must be predicted and applied with great caution as this basic metric is far from simple.
自中国武汉市疫情爆发以来，疫情的预测和预估一直是研究人员关注的领域，而基本再生数R0始终是备受青睐的工具。基本再生数（R0）既可以是比率、速率，也可以是基本繁殖率。这个无量纲数过去曾用于描述多种传染病病原体的传染性或传播性。在新冠疫情背景下，它的重要性丝毫不减，它能告诉我们为预防疾病应采取哪些公共卫生措施，以及新冠病毒的传播将如何受到影响或被阻断。R0受多种决定病原体传播的生物学、社会行为学和环境因素影响。R0是通过复杂的数学模型估算出来的，其结果很容易被扭曲、误判和滥用。R0并非某种病原体的生物学常数，而是一个随时间变化的速率。它可以衡量疾病的严重程度，还能对扭转疫情所需的群体免疫水平给出估计。尽管R0能告诉我们人群免疫状态与疫情曲线之间的关系，但它无法通过疫苗接种活动改变。建模得到的R0值取决于模型结构和所作的假设。科学文献中报道的一些R0值可能已经过时，因为在当前疫情中假设经常变化。由于这个基本指标远非简单，所以对R0进行预测和应用时必须格外谨慎。
