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.
【저자키워드】 Infectious diseases, Vaccines, 【초록키워드】 neutralizing antibody, SARS-CoV-2, Efficacy, Vaccine, COVID-19 vaccine, immune response, Trial, Neutralizing antibodies, antibody, neutralization, vaccine efficacy, Population, asymptomatic infections, Randomized, COVID-19 vaccines, AZD1222, pseudovirus, B.1.1.7, International, asymptomatic infection, Alpha, antibody levels, estimate, United Kingdom, ChAdOx1, ChAdOx1 nCoV-19, Anti-spike, neutralization titers, binding, symptomatic infection, marker, Predictive, Antibody Units, international unit, reduced risk, recipients, significance level, second dose, These data, Anti-RBD antibodies, neutralization titer, immune markers, extrapolation, binding antibody units, binding and neutralizing antibodies, variant of SARS-CoV-2, analyzed, assays, facilitate, can be used, majority, determine, correlated, elicited, were measured, binding antibody unit, immune marker, normalized, not correlated, 【제목키워드】 SARS-COV-2 infection, symptomatic and asymptomatic,