SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion
By P. Mlcochova, S. Kemp, M. S. Dhar, G. Papa, B. Meng, I. Ferreira, R. Datir, D. Collier, A. Albecka, S. Singh and 42 more. Nature, 2021
1,134 citations recorded by the source corpus.
The B.1.617.2 (Delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha)1. In vitro, B.1.617.2 is sixfold less sensitive to serum neutralizing antibodies from recovered individuals, and eightfold less sensitive to vaccine-elicited antibodies, compared with wild-type Wuhan-1 bearing D614G. Serum neutralizing titres against B.1.617.2 were lower in ChAdOx1 vaccinees than in BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies to the receptor-binding domain and the amino-terminal domain. B.1.617.2 demonstrated higher replication efficiency than B.1.1.7 in both airway organoid and human airway epithelial systems, associated with B.1.617.2 spike being in a predominantly cleaved state compared with B.1.1.7 spike. The B.1.617.2 spike protein was able to mediate highly efficient syncytium formation that was less sensitive to inhibition by neutralizing antibody, compared with that of wild-type spike. We also observed that B.1.617.2 had higher replication and spike-mediated entry than B.1.617.1, potentially explaining the B.1.617.2 dominance. In an analysis of more than 130 SARS-CoV-2-infected health care workers across three centres in India during a period of mixed lineage circulation, we observed reduced ChAdOx1 vaccine effectiveness against B.1.617.2 relative to non-B.1.617.2, with the caveat of possible residual confounding. Compromised vaccine efficacy against the highly fit and immune-evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era. A study of SARS-CoV-2 variants examining their transmission, infectivity, and potential resistance to therapies provides insights into the biology of the Delta variant and its role in the global pandemic.
Subfields: Infectious Diseases
View Paper: https://www.semanticscholar.org/paper/ff25d53950f382ca8d506c8e8a4a0a72eb912c9d
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Citations in the corpus
- Outbreak.info genomic reports: scalable and dynamic surveillance of SARS-CoV-2 variants and mutations (2023, positive): “The Delta variant of SARS-CoV-2 was first detected in Maharashtra, India in December 2020 [38], has been shown to be 40%-60% more transmissible than Alpha [42,43], and causes a reduction in vaccine efficacy relative to previously circulating lineages [44].”
- mRNA-based COVID-19 vaccine boosters induce neutralizing immunity against SARS-CoV-2 Omicron variant (2021, positive): “Neutralization of the Delta variant pseudovirus was decreased relative towild type for all subgroups (Figure 2C), as has beenpreviously reported (Mlcochova et al., 2021; Planas et al., 2021).”
- Attenuated fusogenicity and pathogenicity of SARS-CoV-2 Omicron variant (2022, positive): “Consistent with our previous studies 2,3 , in the S-expressing cells, the level of the cleaved S2 subunit was higher for Delta S than for the D614G-bearing parental S (Fig.”
- SARS-CoV-2 vaccination induces immunological T cell memory able to cross-recognize variants from Alpha to Omicron (2022, neutral): “Several additional variants were described more recently (May to Oct 2021) (Chakraborty et al., 2021; Otto et al., 2021), including Mu (B.1.621) (Uriu et al., 2021) and Delta (B.1.617.2) (Mlcochova et al., 2021), with the latter quickly becoming the most dominant SARS-CoV-2 lineage worldwide.”