A group from Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA, etc. has reported about the importance of booster vaccine doses for protection against all Omicron variants.
There are several Omicron sub-lineages with significant variations in their S proteins, including BA.1, BA.1.1, and BA.2. While the constellation of mutations varies between isolates, the BA.1.1 lineage is defined by the presence of a single R346K mutation that is absent from the BA.1 lineage, whereas the BA.2 lineage is defined by key S mutations T19I, L24S, Δ25/27, V213G, T376A, and R408S. Although BA.1 was the major variant during the Omicron wave of the pandemic, the BA.2 variant, and to a lesser extent BA.1.1, has begun to account for an increasing proportion of cases. In particular, the BA.2 variant exhibits enhanced transmissibility relative to BA.1 and can reinfect previously BA.1-infected individuals.
In this study, authors have demonstrated the followings:
Omicron BA.1.1 is effectively neutralized by Omicron patient sera, and Omicron sub-lineages are comparably neutralized by Omicron patient sera.
Omicron BA.1 and BA.2 are resistant to neutralization by two-dose mRNA vaccination but sensitive to neutralization after a booster dose.