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- Title
Immune correlates analysis of a phase 3 trial of the AZD1222 (ChAdOx1 nCoV-19) vaccine.
- Authors
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; Yu, Chenchen
- 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.
- Subjects
PERU; CHILE; CLINICAL trials; COVID-19 vaccines; IMMUNOGLOBULINS; COVID-19 pandemic; VACCINE effectiveness; VIRAL antibodies; VACCINES
- Publication
NPJ Vaccines, 2023, Vol 8, Issue 1, p1
- ISSN
2059-0105
- Publication type
Article
- DOI
10.1038/s41541-023-00630-0