Live virus neutralization testing in convalescent patients and subjects vaccinated against 19A, 20B, 20I/501Y.V1 and 20H/501Y.V2 isolates of SARS-CoV-2

Emerg Microbes Infect. 2021 Dec;10(1):1499-1502. doi: 10.1080/22221751.2021.1945423.


SARS-CoV-2 mutations appeared recently and can lead to conformational changes in the spike protein and probably induce modifications in antigenicity. We assessed the neutralizing capacity of antibodies to prevent cell infection, using a live virus neutralization test with different strains [19A (initial one), 20B (B.1.1.241 lineage), 20I/501Y.V1 (B.1.1.7 lineage), and 20H/501Y.V2 (B.1.351 lineage)] in serum samples collected from different populations: two-dose vaccinated COVID-19-naive healthcare workers (HCWs; Pfizer-BioNTech BNT161b2), 6-months post mild COVID-19 HCWs, and critical COVID-19 patients. No significant difference was observed between the 20B and 19A isolates for HCWs with mild COVID-19 and critical patients. However, a significant decrease in neutralization ability was found for 20I/501Y.V1 in comparison with 19A isolate for critical patients and HCWs 6-months post infection. Concerning 20H/501Y.V2, all populations had a significant reduction in neutralizing antibody titers in comparison with the 19A isolate. Interestingly, a significant difference in neutralization capacity was observed for vaccinated HCWs between the two variants but not in the convalescent groups.

Keywords: 20B; 20H/501Y.V2; 20I/501Y.V1; SARS-CoV-2; humoral response; live virus neutralization test; variant of concern.

Publication types

  • Letter

MeSH terms

  • Antibodies, Neutralizing / immunology*
  • Antibodies, Viral / immunology*
  • COVID-19 / immunology*
  • COVID-19 / prevention & control
  • COVID-19 / virology
  • COVID-19 Vaccines / administration & dosage
  • COVID-19 Vaccines / genetics
  • COVID-19 Vaccines / immunology*
  • Humans
  • Neutralization Tests
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / immunology*
  • SARS-CoV-2 / isolation & purification


  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19 Vaccines

Grants and funding

This research is being supported by Hospices Civils de Lyon, Fondation des Hospices Civils de Lyon, and a grant from the GIMAP team of the University Hospital of Saint-Etienne (Grant reference: the ASSE Coeur-vert association).