The most interesting bit:<p>"Persistent neutralization of the wide-spread Alpha and Delta variants one year after wild-type infection may aid vaccine policy makers in low-resource settings when prioritizing vaccine supply. The reduced capacity of neutralizing Beta and Gamma strains, but not the Alpha and Delta strains following both infection and three different vaccine regimens argues for caution against Beta and Gamma-exclusive mutations in the efforts to optimize next generation SARS-CoV-2 vaccines."<p>The ability of Delta to spread more rapidly than Beta or Gamma, does not appear to be based on superior ability to infect previously infected or vaccinated people. Which is good news, really, but also raises the question of, why is it spreading faster than Beta or Gamma, then?