Feng, Shuo; Phillips, Daniel J; White, Thomas; Sayal, Homesh; Aley, Parvinder K; Bibi, Sagida; Dold, Christina; Fuskova, Michelle; Gilbert, Sarah C; Hirsch, Ian; +12 more... Humphries, Holly E; Jepson, Brett; Kelly, Elizabeth J; Plested, Emma; Shoemaker, Kathryn; Thomas, Kelly M; Vekemans, Johan; Villafana, Tonya L; Lambe, Teresa; Pollard, Andrew J; Voysey, Merryn; Oxford COVID Vaccine Trial Group; (2021) Correlates of protection against symptomatic and asymptomatic SARS-CoV-2 infection. Nature medicine, 27 (11). pp. 2032-2040. ISSN 1078-8956 DOI: https://doi.org/10.1038/s41591-021-01540-1
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Abstract
The global supply of COVID-19 vaccines remains limited. An understanding of the immune response that is predictive of protection could facilitate rapid licensure of new vaccines. Data from a randomized efficacy trial of the ChAdOx1 nCoV-19 (AZD1222) vaccine in the United Kingdom was analyzed to determine the antibody levels associated with protection against SARS-CoV-2. Binding and neutralizing antibodies at 28 days after the second dose were measured in infected and noninfected vaccine recipients. Higher levels of all immune markers were correlated with a reduced risk of symptomatic infection. A vaccine efficacy of 80% against symptomatic infection with majority Alpha (B.1.1.7) variant of SARS-CoV-2 was achieved with 264 (95% CI: 108, 806) binding antibody units (BAU)/ml: and 506 (95% CI: 135, not computed (beyond data range) (NC)) BAU/ml for anti-spike and anti-RBD antibodies, and 26 (95% CI: NC, NC) international unit (IU)/ml and 247 (95% CI: 101, NC) normalized neutralization titers (NF50) for pseudovirus and live-virus neutralization, respectively. Immune markers were not correlated with asymptomatic infections at the 5% significance level. These data can be used to bridge to new populations using validated assays, and allow extrapolation of efficacy estimates to new COVID-19 vaccines.
Item Type | Article |
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Research Centre | Covid-19 Research |
PubMed ID | 34588689 |
Elements ID | 166716 |
Official URL | http://dx.doi.org/10.1038/s41591-021-01540-1 |
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Filename: Feng_etal_2021_Correlates-of-protection-against-symptomatic.pdf
Licence: Creative Commons: Attribution 4.0
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