EBioMedicine (Apr 2022)

Sub-optimal neutralisation of omicron (B.1.1.529) variant by antibodies induced by vaccine alone or SARS-CoV-2 Infection plus vaccine (hybrid immunity) post 6-months

  • Guruprasad R Medigeshi,
  • Gaurav Batra,
  • Deepika Rathna Murugesan,
  • Ramachandran Thiruvengadam,
  • Souvick Chattopadhyay,
  • Bhabatosh Das,
  • Mudita Gosain,
  • Ayushi,
  • Janmejay Singh,
  • Anantharaj Anbalagan,
  • Heena Shaman,
  • Kamal Pargai,
  • Farha Mehdi,
  • Soon Jyoti Das,
  • Namrata Kahlon,
  • Savita Singh,
  • Pallavi Kshetrapal,
  • Nitya Wadhwa,
  • Anil K Pandey,
  • Shinjini Bhatnagar,
  • Pramod Kumar Garg

Journal volume & issue
Vol. 78
p. 103938

Abstract

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Summary: Background: Rapid spread of the omicron SARS-CoV-2 variant despite extensive vaccination suggests immune escape. The neutralising ability of different vaccines alone or with natural SARS-CoV-2 infection against omicron is not well-known. Methods: In this cross-sectional study, we tested the ability of vaccine and natural infection induced antibodies to neutralise omicron variant in a live virus neutralisation assay in four groups of individuals: (i) ChAdOx1 nCoV-19 vaccination, (ii) ChAdOx1 nCoV-19 vaccination plus prior SARS-CoV-2 infection, (iii) vaccination with inactivated virus vaccine (BBV152), and (iv) BBV152 vaccination plus prior SARS-CoV-2 infection. Primary outcome was fold-change in virus neutralisation titre against omicron compared with ancestral virus. Findings: We included 80 subjects. The geometric mean titre (GMT) of the 50% focus reduction neutralisation test (FRNT50) was 380·4 (95% CI: 221·1, 654·7) against the ancestral virus with BBV152 vaccination and 379·3 (95% CI: 185·6, 775·2) with ChAdOx1 nCov-19 vaccination alone. GMT for vaccination plus infection groups were 806·1 (95% CI: 478·5, 1357·8) and 1526·2 (95% CI: 853·2, 2730·0), respectively. Against omicron variant, only 5 out of 20 in both BBV152 and ChAdOx1 nCoV-19 vaccine only groups, 6 out of 20 in BBV152 plus prior SARS-CoV-2 infection group, and 9 out of 20 in ChAdOx1 nCoV-19 plus prior SARS-CoV-2 infection group exhibited neutralisation titres above the lower limit of quantification (1:20) suggesting better neutralisation with prior infection. A reduction of 26·6 and 25·7 fold in FRNT50 titres against Omicron compared to ancestral SARS-CoV-2 strain was observed for individuals without prior SARS-CoV-2 infection vaccinated with BBV152 and ChAdOx1 nCoV-19, respectively. The corresponding reduction was 57·1 and 58·1 fold, respectively, for vaccinated individuals with prior infection. The 50% neutralisation titre against omicron demonstrated moderate correlation with serum anti-RBD IgG levels [Spearman r: 0·58 (0·41, 0·71)]. Interpretation: Significant reduction in the neutralising ability of both vaccine-induced and vaccine plus infection-induced antibodies was observed for omicron variant which might explain immune escape. Funding: Department of Biotechnology, India; Bill & Melinda Gates Foundation, USA

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