Mapping the evolution and diversity of influenza B viruses

Title: Mapping the evolution and diversity of influenza B viruses

Speaker: Dr Marios Koutsakos, University of Melbourne

Abstract: Influenza B viruses (IBV) circulate annually and have considerable clinical burden, which is particularly severe in children. However, they are generally overlooked compared to influenza A viruses. This is largely because they are considered an exclusive human pathogen with no established animal reservoir and therefore no pandemic potential. While IBV is included in the annual influenza vaccine formulation, vaccine efficacy varies greatly and IBV undergoes continuous antigenic drift. This seminar will describe the antigenic characterisation of IBVs from 1940-2021, the molecular basis of antigenic drift, and the role of epistasis in facilitating antigenic change while balancing viral fitness. It will further describe a global seroprevalence study, analysing >1900 serum samples from 9 species of pinnipeds (seals and sea lions) collected between 1998-2025 across North and South America, Australia and South Africa, as well as Antarctica and sub-Antarctic islands. The consistent detection of IBV-specific antibodies across time, geographic regions and pinniped species challenges the prevailing notion that IBV is exclusively circulating in humans. Overall, this work maps the antigenic diversity of human IBVs and highlights an unappreciated aspect of IBV ecology that warrants further investigation to assess the potential threat such viruses pose to humans and other animals. 

Bio: Dr Marios Koutsakos undertook a PhD with Professor Katherine Kedzierska within the Department of Microbiology and Immunology, University of Melbourne, focusing on understanding protective immunity to influenza viruses, with special focus on IBV. He is now a Group Leader at the Department of Microbiology and Immunology, University of Melbourne at the Doherty Institute, leading a group focused on understanding the antigenic diversity and evolution of influenza viruses. He is the recipient of an NHMRC EL1 fellowship, the Locarnini-Morningside Fellowship in Virology, a CGCPT Foundation Grant and an NHMRC EL2 fellowship. He has received numerous awards, including the NHMRC Frank Fenner award for research excellence, the NARF Postdoctoral Scientist award, the Vaccine Congress Early Career Scientist Award and the ESWI Vaccine Innovation Award.