TY - JOUR
T1 - Correlates of severe and delta COVID-19 in a phase 3 trial of the AZD1222 vaccine
AU - AstraZeneca AZD1222 Clinical Study Group
AU - the Immune Assays Team
AU - the United States Government (USG)/CoVPN Biostatistics Team
AU - Janes, Holly
AU - Fong, Youyi
AU - Huang, Ying
AU - Benkeser, David
AU - Kelly, Elizabeth J.
AU - Hirsch, Ian
AU - Stanley, Ann Marie
AU - Villafana, Tonya
AU - Petropoulos, Christos J.
AU - Leith, Andrew
AU - Haugaard, Deanne
AU - Webb, Bill
AU - Lu, Yiwen
AU - Yu, Chenchen
AU - Borate, Bhavesh
AU - van der Laan, Lars W.P.
AU - Hejazi, Nima S.
AU - Randhawa, April K.
AU - Andrasik, Michele P.
AU - Kublin, James G.
AU - Isaacs, Margaret Brewinski
AU - Makhene, Mamodikoe
AU - Tong, Tina
AU - Robb, Merlin L.
AU - Corey, Lawrence
AU - Neuzil, Kathleen M.
AU - Follmann, Dean
AU - Falsey, Ann R.
AU - Sobieszczyk, Magdalena E.
AU - Koup, Richard A.
AU - Gilbert, Peter B.
N1 - Publisher Copyright:
© The Author(s) 2026.
PY - 2026/12
Y1 - 2026/12
N2 - In the phase 3 AZD1222 COVID-19 vaccine trial, anti-Spike (vaccine-matched and Delta) binding IgG antibody concentration and neutralizing antibody (nAb) titer (vaccine-matched+D614G and Delta), measured four weeks post-dose two (D57), were assessed as correlates of risk of severe COVID-19 and Delta COVID-19 over ~4 to ~13 months (severe) or ~11 months (Delta) post-D57. Using a case-control design, antibodies were measured in baseline SARS-CoV-2-negative per-protocol ChAdOx1 nCoV-19 recipients (19 severe COVID-19 cases, 57 Delta COVID-19 cases, 111 controls). The hazard ratio (HR) of severe COVID-19 per 10-fold vaccine-matched D57 marker increase was 0.16 (95% CI: 0.05, 0.54; p = 0.004) for Spike IgG and 0.13 (0.03, 0.59; p = 0.009) for nAb titer. D57 Delta antibodies were weak correlates of Delta COVID-19: HR per 10-fold increase 0.70 (0.14, 3.47; p = 0.66) for Delta Spike IgG; 0.46 (0.14, 1.47; p = 0.19) for Delta nAb titer. Binding and nAb levels strongly predicted severe COVID-19, even with antibody waning.
AB - In the phase 3 AZD1222 COVID-19 vaccine trial, anti-Spike (vaccine-matched and Delta) binding IgG antibody concentration and neutralizing antibody (nAb) titer (vaccine-matched+D614G and Delta), measured four weeks post-dose two (D57), were assessed as correlates of risk of severe COVID-19 and Delta COVID-19 over ~4 to ~13 months (severe) or ~11 months (Delta) post-D57. Using a case-control design, antibodies were measured in baseline SARS-CoV-2-negative per-protocol ChAdOx1 nCoV-19 recipients (19 severe COVID-19 cases, 57 Delta COVID-19 cases, 111 controls). The hazard ratio (HR) of severe COVID-19 per 10-fold vaccine-matched D57 marker increase was 0.16 (95% CI: 0.05, 0.54; p = 0.004) for Spike IgG and 0.13 (0.03, 0.59; p = 0.009) for nAb titer. D57 Delta antibodies were weak correlates of Delta COVID-19: HR per 10-fold increase 0.70 (0.14, 3.47; p = 0.66) for Delta Spike IgG; 0.46 (0.14, 1.47; p = 0.19) for Delta nAb titer. Binding and nAb levels strongly predicted severe COVID-19, even with antibody waning.
UR - https://www.scopus.com/pages/publications/105042400228
U2 - 10.1038/s41541-026-01411-1
DO - 10.1038/s41541-026-01411-1
M3 - Article
AN - SCOPUS:105042400228
SN - 2059-0105
VL - 11
JO - npj Vaccines
JF - npj Vaccines
IS - 1
M1 - 120
ER -