Abstract
In late November 2021, the World Health Organization declared the SARS-CoV-2 lineage B.1.1.529 the fifth variant of concern, Omicron. This variant has acquired 15 mutations in the receptor binding domain of the spike protein, raising concerns that Omicron could evade naturally acquired and vaccine-derived immunity. We utilized an authentic virus, multicycle neutralisation assay to demonstrate that sera collected 1, 3, and 6 months post-two doses of Pfizer-BioNTech BNT162b2 has a limited ability to neutralise SARS-CoV-2. However, four weeks after a third dose, neutralizing antibody titres are boosted. Despite this increase, neutralising antibody titres are reduced 4-fold for Omicron compared to lineage A.2.2 SARS-CoV-2.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
↵† Joint first authors
