1. Immune correlates analysis of a phase 3 trial of the AZD1222 (ChAdOx1 nCoV-19) vaccine.
- Author
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Benkeser, David, Fong, Youyi, Janes, Holly E., Kelly, Elizabeth J., Hirsch, Ian, Sproule, Stephanie, Stanley, Ann Marie, Maaske, Jill, Villafana, Tonya, Houchens, Christopher R., Martins, Karen, Jayashankar, Lakshmi, Castellino, Flora, Ayala, Victor, Petropoulos, Christos J., Leith, Andrew, Haugaard, Deanne, Webb, Bill, Lu, Yiwen, and Yu, Chenchen
- Subjects
CLINICAL trials ,COVID-19 vaccines ,IMMUNOGLOBULINS ,COVID-19 pandemic ,VACCINE effectiveness ,VIRAL antibodies ,VACCINES - Abstract
In the phase 3 trial of the AZD1222 (ChAdOx1 nCoV-19) vaccine conducted in the U.S., Chile, and Peru, anti-spike binding IgG concentration (spike IgG) and pseudovirus 50% neutralizing antibody titer (nAb ID50) measured four weeks after two doses were assessed as correlates of risk and protection against PCR-confirmed symptomatic SARS-CoV-2 infection (COVID-19). These analyses of SARS-CoV-2 negative participants were based on case-cohort sampling of vaccine recipients (33 COVID-19 cases by 4 months post dose two, 463 non-cases). The adjusted hazard ratio of COVID-19 was 0.32 (95% CI: 0.14, 0.76) per 10-fold increase in spike IgG concentration and 0.28 (0.10, 0.77) per 10-fold increase in nAb ID50 titer. At nAb ID50 below the limit of detection (< 2.612 IU50/ml), 10, 100, and 270 IU50/ml, vaccine efficacy was −5.8% (−651%, 75.6%), 64.9% (56.4%, 86.9%), 90.0% (55.8%, 97.6%) and 94.2% (69.4%, 99.1%). These findings provide further evidence towards defining an immune marker correlate of protection to help guide regulatory/approval decisions for COVID-19 vaccines. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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