Epidemiology Answers Key Questions About Delta Variant Transmissibility And Lethality

Understanding the transmission dynamics of SARS-CoV-2 infection is critical to developing countermeasures that can successfully stop the spread of the virus. For most of the Covid-19 pandemic, computational modeling studies have given us a general sense of when, following infection, SARS-CoV-2 becomes contagious, then symptomatic. But due to difficulties in data collection, the exact timing of this progression eluded us. That is, until this past August, when a group of Chinese researchers published a preprint study of an outbreak of the Delta variant in Guangdong province. Their study pinpoints, with unprecedented precision, exactly when in the disease course infectivity and symptom onset might be expected. And in the broader context of epidemiological research and disease control, the study is an excellent example of the level of insight possible when public health measures, including contact tracing, are systematically combined with cutting-edge virology and pathology. In May 2021, public health officials in Guangzhou, China began tracking an outbreak of Covid-19 cases caused by the highly infectious Delta variant of SARS-CoV-2. Through rigorous PCR testing and contact tracing protocols, they identified infected individuals and controlled the outbreak by June. The authors of the study, Kang et. al, drew from this pool of epidemiological data to determine how long it takes the Delta variant, as compared to the original wild type virus, to become infectious and cause symptoms in the people it infects. They aggregated data on a total of 167 Covid-19 patients. Read full article on Forbes Originally published on Forbes (November 16, 2021)
© William A. Haseltine, PhD. All Rights Reserved.