A characteristic of respiratory viruses is their ability to continue circulating despite the accumulated population immunity due to infections, and in the case of influenza, the use of vaccines. A genetic bottlenecking due to case reduction during the COVID-19 pandemic has, however, resulted in reduced genetic diversity of influenza virus, which may greatly impact vaccine formulations. According to the WHO FluNet and GISAID platforms there has been a dramatic reduction in influenza B/Yamagata detections reported, with none confirmed by sequencing after March 2020. Using the GISAID and FluNet platforms we will monitor influenza circulation, at least up to the end of the 2023 influenza season in the Southern Hemisphere, and will investigate the possible extinction of the B/Yamagata virus lineage. If this lineage is no longer circulating, whether this viral antigen needs to be included in the composition of quadrivalent influenza vaccines needs to be interrogated.