RESEARCH BRIEFINGS 23 December 2021 Delphine Planas 0 , Nell Saunders 1 , Piet Maes 2 , Florence Guivel-Benhassine 3 , Cyril Planchais 4 , Julian Buchrieser 5 , William-Henry Bolland 6 , Françoise Porrot 7 , Isabelle Staropoli 8 , Frederic Lemoine 9 , Hélène Péré 10 , David Veyer 11 , Julien Puech 12 , Julien Rodary 13 , Guy Baela 14 , Simon Dellicour 15 , Joren Raymenants 16 , Sarah Gorissen 17 , Caspar Geenen 18 , Bert Vanmechelen 19 , Tony Wawina-Bokalanga 20 , Joan Martí-Carrerasi 21 , Lize Cuypers 22 , Aymeric Sève 23 , Laurent Hocqueloux 24 , Thierry Prazuck 25 , Félix Rey 26 , Etienne Simon-Lorrière 27 , Timothée Bruel 28 , Hugo Mouquet 29 , Emmanuel André 30 & Olivier Schwartz 31
This manuscript has been peer reviewed and accepted for publication in Nature and is provided in this format here as a response to the exceptional public-health crisis. This accepted manuscript will continue through the processes of copy editing and formatting to publication of a finalized version of record on nature.com. Please note there may be errors present in this version, which may affect the content, and all legal disclaimers apply. The SARS-CoV-2 Omicron variant was first identified in November 2021 in Botswana and South Africa 1,2,3. It has since then spread to many countries and is expected to rapidly become dominant worldwide. The lineage is characterized by the presence of about 32 mutations in the spike, located mostly in the N-terminal domain (NTD) and the receptor binding domain (RBD), which may enhance viral fitness and allow antibody evasion. Here, we isolated an infectious Omicron virus in Belgium, from a traveller returning from Egypt. We examined its sensitivity to 9 monoclonal antibodies (mAbs) clinically approved or in development4, and to antibodies present in 115 sera from COVID-19 vaccine recipients or convalescent individuals. Omicron was totally or partially resistant to neutralization by all mAbs tested. Sera from Pfizer or AstraZeneca vaccine recipients, sampled 5 months after complete vaccination, barely inhibited Omicron. Sera from COVID-19 convalescent patients collected 6 or 12 months post symptoms displayed low or no neutralizing activity against Omicron. Administration of a booster Pfizer dose as well as vaccination of previously infected individuals generated an anti-Omicron neutralizing response, with titers 6 to 23 fold lower against Omicron than against Delta. Thus, Omicron escapes most therapeutic monoclonal antibodies and to a large extent vaccine-elicited antibodies. Omicron remains however neutralized by antibodies generated by a booster vaccine dose. doi: https://doi.org/10.1038/d41586-021-03827-2 Supplementary Information
https://www.nature.com/articles/d41586-021-03827-2
