Journal Article

Correlates of protection against symptomatic and asymptomatic SARS-CoV-2 infection

Fuskova, Michelle, Bibi, Sagida, Sayal, Homesh, Plested, Emma, White, Thomas, Shoemaker, Kathryn, Lambe, Teresa, Feng, Shuo, Kelly, Elizabeth J., Phillips, Daniel J., Aley, Parvinder K., Villafana, Tonya L., Jepson, Brett, Gilbert, Sarah C., Dold, Christina, Pollard, Andrew J., Voysey, Merryn, Hirsch, Ian, Thomas, Kelly M., Humphries, Holly E., Vekemans, Johan

2021

Overview

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 (NF 50 ) 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. Defined levels of SARS-CoV-2-specific binding and neutralizing antibodies elicited by the COVID-19 vaccine ChAdOx1 nCoV-19 are identified as correlates of protection against symptomatic infection.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: 631/250/255 / 631/250/590 / Adolescent / Adult / Aged / Aged, 80 and over / Analysis / Antibodies / Antibodies, Neutralizing - blood / Antibodies, Viral - blood / Asymptomatic / Asymptomatic Infections / Binding / Biomedical and Life Sciences / Biomedicine / Cancer Research / Cohort Studies / Coronaviruses / Correlation / COVID-19 / COVID-19 - epidemiology / COVID-19 - immunology / COVID-19 - pathology / COVID-19 - prevention & control / COVID-19 vaccines / COVID-19 Vaccines - genetics / COVID-19 Vaccines - immunology / COVID-19 Vaccines - therapeutic use / Female / Humans / Immune response / Immune system / Immunity, Humoral / Immunization, Secondary / Infection Control - statistics & numerical data / Infections / Infectious Diseases / Male / Markers / Measurement / Metabolic Diseases / Middle Aged / Molecular Medicine / Neurosciences / Neutralization / Neutralizing / Patient Acuity / Risk management / SARS-CoV-2 - genetics / SARS-CoV-2 - immunology / Severe acute respiratory syndrome coronavirus 2 / Treatment Outcome / United Kingdom - epidemiology / Vaccination / Vaccine efficacy / Vaccines / Viral antibodies / Viral diseases / Young Adult