CHMP5 and influenza: To contextualize the sequences of vaccine strains, we conducted phylogenetic analysis using all the available HA gene sequences of influenza A/H1N1, A/H3N2, A/H5N1, A/H7N9, B/Yamgata, and B/Victoria collected since 2000, as well as all available SARS-CoV-2 spike genes (Fig. 1B and C).