SARS-CoV-2 variants
…mRNA-based vaccines (Pfizer and Moderna), and more challenging for others, like the virus-vectored vaccines (AstraZeneca and Johnson & Johnson). Eventually, it would be desirable to develop vaccines that target regions of the SARS-CoV-2 spike where mutations would prevent the virus from functioning, such as the S2 region. Influenza A virus vaccines provide a useful analogy….