+1 Recommend
1 collections
      • Record: found
      • Abstract: found
      • Article: not found

      SARS-CoV-2 Omicron triggers cross-reactive neutralization and Fc effector functions in previously vaccinated, but not unvaccinated individuals


      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.


          The SARS-CoV-2 Omicron variant escapes neutralizing antibodies elicited by vaccines or infection. However, whether Omicron triggers cross-reactive humoral responses to other variants of concern (VOCs) remains unknown. We use plasma from 20 unvaccinated and seven vaccinated individuals infected by Omicron BA.1 to test binding, Fc effector function and neutralization against VOCs. In unvaccinated individuals, Fc effector function and binding antibodies target Omicron and other VOCs at comparable levels. However, Omicron BA.1-triggered neutralization is not extensively cross-reactive for VOCs (14 to 31-fold titer reduction) and we observe 4-fold decreased titers against Omicron BA.2. In contrast, vaccination followed by breakthrough Omicron infection associates with improved cross-neutralization of VOCs, with titers exceeding 1:2,100. This has important implications for vulnerability of unvaccinated Omicron-infected individuals to reinfection by circulating and emerging VOCs. While Omicron-based immunogens may be adequate boosters, they are unlikely to be superior to existing vaccines for priming in SARS-CoV-2 naïve individuals.

          Graphical abstract


          Richardson et al. show that SARS-CoV-2 Omicron infection in unvaccinated individuals triggers potent antibody responses; however, cross-reactivity against variants of concern is poor. In contrast, Omicron BA.1 breakthrough infection in vaccinated individuals elicits high titer cross-reactive antibodies. Omicron-based vaccines are thus unlikely to be superior immunogens in SARS-COV-2 naïve individuals.

          Related collections

          Author and article information

          Cell Host Microbe
          Cell Host Microbe
          Cell Host & Microbe
          Published by Elsevier Inc.
          25 March 2022
          25 March 2022
          [1 ]National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
          [2 ]MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
          [3 ]Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
          [4 ]Zoonotic Arbo and Respiratory Virus Program, Centre for Viral Zoonoses, Department of Medical Virology, University of Pretoria, Pretoria, South Africa
          [5 ]KwaZulu-Natal Research Innovation and Sequencing Platform, Durban, South Africa; Centre for Epidemic Response and Innovation, School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
          [6 ]Tshwane District Hospital, Pretoria, South Africa
          [7 ]Division for Infectious Diseases, Department of Internal Medicine, Steve Biko Academic Hospital and University of Pretoria, Pretoria, South Africa
          [8 ]Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
          [9 ]Centre for the AIDS Programme of Research in South Africa, Durban, South Africa
          Author notes
          []Lead Contact: Penny L. Moore Email:
          © 2022 Published by Elsevier Inc.

          Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre - including this research content - immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

          : 11 February 2022
          : 11 March 2022
          : 22 March 2022
          Brief Report

          Microbiology & Virology
          Microbiology & Virology


          Comment on this article