As respiratory viruses with proven pandemic potential, SARS-CoV-2 and influenza share several features including zoonotic origin and airborne spread. The development, manufacture and deployment of effective SARS-CoV-2 vaccines using different platforms is a remarkable success story. But we are now faced with a decline in immunity over time and the emergence of variant viruses against which vaccine effectiveness is reduced. The spread of variants with mutations in the S protein’s receptor binding domain have raised concerns that COVID-19 vaccines may have to be updated because some mutations can render the variants less optimally targeted by current vaccines. Experience with influenza vaccines that can inform the framework for considering updates in SARS-CoV-2 vaccine composition will be discussed.