Correlates of protection against symptomatic and asymptomatic SARS-CoV-2 infection.
Nat Med
; 27(11): 2032-2040, 2021 11.
Article
in En
| MEDLINE
| ID: mdl-34588689
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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Immunity, Humoral
/
COVID-19 Vaccines
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SARS-CoV-2
/
COVID-19
Type of study:
Clinical_trials
/
Diagnostic_studies
/
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Aspects:
Patient_preference
Limits:
Adolescent
/
Adult
/
Aged
/
Aged80
/
Female
/
Humans
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Male
/
Middle aged
Country/Region as subject:
Europa
Language:
En
Journal:
Nat Med
Journal subject:
BIOLOGIA MOLECULAR
/
MEDICINA
Year:
2021
Document type:
Article
Affiliation country: