Join us for a conversation with Katia Koelle, Associate Professor of Biology at Emory University. During a transmission event, viral particles from a donor seed infection in a recipient individual. If a small number of viral particles seed the infection, transmission bottlenecks are said to be stringent or narrow. Alternatively, transmission bottlenecks can be loose or wide. We have in the past developed statistical methods to quantify transmission bottleneck sizes, and here will discuss our work and that of others that have applied these methods to SARS-CoV-2. We find that SARS-CoV-2, like seasonal influenza viruses, have extremely narrow bottlenecks of fewer than 5 particles. We discuss the implications of these results for viral evolution and adaptation at the population level, and their implications for reconstructing who-infected-whom in smaller outbreaks.
Attendees are encouraged to read the Martin and Koelle preprint, “Reanalysis of deep-sequencing data from Austria points towards a small SARS-CoV-2 transmission bottleneck on the order of one to three virions” and Lythgoe et al. 2021, “SARS-CoV-2 within-host diversity and transmission.” Sign up here for the meeting link.