Neutralization of SARS-CoV-2 Omicron sub-lineages BA.1, BA.1.1, and BA.2

Recent reports of SARS-CoV-2 Omicron variant sub-lineages, BA.1, BA.1 .1 , and BA.2, have reignited concern over potential escape from vaccine- and infection-induced immunity. We examine the sensitivity of these sub-lineages and other major variants to neutralizing antibodies from mRNA-vaccinated and boosted individuals, as well as recovered COVID-19 patients, including those infected with Omicron. We find that all Omicron sub-lineages, especially BA.1 and BA.1.1, exhibit substantial immune escape that is largely overcome by mRNA vaccine booster doses. While Omicron BA.1.1 escapes almost completely from neutralization by early-pandemic COVID-1 9 patient sera and to a lesser extent from sera of Delta-infected patients, BA.1.1 is sensitive to Omicron-infected patient sera. Critically, all Omicron sub-lineages, including BA.2, are comparably neutralized by Omicron patient sera. These results highlight the importance of booster vaccine doses for protection against all Omicron variants and provide insight into the immunity from natural infection against Omicron sub-lineages.

Automated summary

Recent reports show that SARS-CoV-2 Omicron variant sub-lineages BA.1, BA.1.1, and BA.2 have raised concerns about their ability to escape vaccine-induced and infection-induced immunity. A study finds that all Omicron sub-lineages, especially BA.1 and BA.1.1, exhibit significant immune escape, but this can be largely overcome by mRNA vaccine booster doses. The findings highlight the importance of booster vaccine doses for protection against all Omicron variants and provide insights into the immunity from natural infection against Omicron sub-lineages.