5/27/21 CDC update on variants

Per the update:

 "Sera from mRNA COVID-19 vaccine (both Pfizer-BioNTech and Moderna) recipients have demonstrated minimal to large reductions in antibody neutralization activity against a variety of mutations.(62-106). Across studies of VOC, the greatest reductions were observed for B.1.351, followed by P.1; reductions for B.1.1.7 and B.1.427/B.1.429 were minimal. A limited number of studies were available for some VOI that demonstrated greater reductions for P.2, B.1.525, and B.1.617.1 and minimal reductions for B.1.617 and B.1.526.(67, 84, 86-88, 93-95, 100, 101) The E484K mutation alone or in combination with other mutations in the receptor binding domain has been shown to account for the majority of reduction in vaccine-induced neutralizing antibody activity for the B.1.351, P.1, and P.2 variants.(65, 67, 77, 79, 107) B.1.1.7 and B.1.526 variants with E484K mutations, which have been detected in the United Kingdom, United States, and other countries, have shown further reductions in neutralization above B.1.1.7 and B.1.526 alone, respectively.(62, 65, 81, 84, 86, 93) Two studies have shown that six months after receiving the Moderna vaccine, higher proportions of people had undetectable neutralization activity against B.1.351 and P.1 compared with the ancestral strain.(108, 109) In the absence of a biological correlate of protection, it is difficult to predict how reduced neutralizing activity may affect COVID-19 vaccine effectiveness. However, across studies, antibody neutralizing activity of sera from vaccinated people was generally higher than that observed for convalescent sera from people who have recovered from COVID-19.(65, 66, 68, 72-77, 79, 83, 104, 107)"