Improved Neutralisation of the SARS-CoV-2 Omicron Variant following a Booster Dose of Pfizer-BioNTech (BNT162b2) COVID-19 Vaccine
Kerri Basile, Rebecca J. Rockett, Kenneth McPhie, Michael Fennell, Jessica Johnson-Mackinnon, Jessica E. Agius, Winkie Fong, Hossinur Rahman, Danny Ko, Linda Donavan, Linda Hueston, Connie Lam, Alicia Arnott, Sharon C.‐A. Chen, Susan Maddocks, Matthew O’Sullivan, Dominic E. Dwyer, Vitali Sintchenko, Jen Kok
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 over 30 mutations in the spike protein (with 15 in the receptor-binding domain), 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 one, three, and six months post-two doses of Pfizer-BioNTech BNT162b2 had a limited ability to neutralise SARS-CoV-2. However, four weeks after a third dose, neutralising antibody titres were boosted. Despite this increase, neutralising antibody titres were reduced fourfold for Omicron compared to lineage A.2.2 SARS-CoV-2.