ABSTRACT
Waning immunity following mRNA vaccination and the emergence of SARS-CoV-2 variants has led to reduced mRNA vaccine efficacy against both symptomatic infection and severe disease. Bivalent mRNA boosters expressing the Omicron BA.5 and ancestral WA1/2020 Spike proteins have been developed and approved, because BA.5 is currently the dominant SARS-CoV-2 variant and substantially evades neutralizing antibodies (NAbs). Our data show that BA.5 NAb titers were comparable following monovalent and bivalent mRNA boosters.
ABSTRACT
Multiple lineages of the SARS-CoV-2 Omicron variant (B.1.1.529) have emerged, and BA.1 and BA.2 have demonstrated substantial escape from neutralizing antibodies (NAbs). BA.2.12.1 has now become dominant in the United States, and BA.4 and BA.5 have become dominant in South Africa. Our data show that BA.2.12.1 and BA.4/BA.5 substantially escape NAbs induced by both vaccination and infection. Moreover, BA.4/BA.5 NAb titers, and to lesser extent BA.2.12.1 NAb titers, were lower than BA.1 and BA.2 NAb titers, suggesting that the SARS-CoV-2 Omicron variant has continued to evolve with increasing neutralization escape. These findings have important public health implications and provide immunologic context for the current surges with BA.2.12.1 and BA.4/BA.5 in populations with high rates of vaccination and BA.1/BA.2 infection.
