Long-Term Safety and Immunogenicity of AZD1222 (ChAdOx1 nCoV-19): 2-Year Follow-Up from a Phase 3 Study

Kathryn Shoemaker, Biometrics, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA.
Karina Soboleva, Clinical Development, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA.
Angela Branche, Division of Infectious Diseases, Department of Medicine, University of Rochester, Rochester, NY 14627, USA.
Shivanjali Shankaran, Division of Infectious Diseases, Rush University Medical Center, Chicago, IL 60612, USA.
Deborah A. Theodore, Division of Infectious Diseases, Department of Medicine, Vagelos College of Physicians and Surgeons, New York-Presbyterian/Columbia University Irving Medical Center, New York, NY 10032, USA.
Muhammad Bari, Formerly Patient Safety, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Cambridge CB2 0AA, UK.
Victor Ezeh, Clinical Development, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA.
Justin Green, Clinical Development, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Cambridge CB2 0AA, UK.
Elizabeth Kelly, Formerly Translational Medicine, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA.
Dongmei Lan, Biometrics, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA.
Urban Olsson, Clinical Development, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, 431 83 Gothenburg, Sweden.
Senthilkumar Saminathan, Patient Safety, Chief Medical Office, R&D, AstraZeneca, Bangalore 560045, India.
Nirmal Kumar Shankar, Patient Safety, Chief Medical Office, R&D, AstraZeneca, Bangalore 560045, India.
Berta Villegas, Clinical Operations, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Mississauga, ON L4Y 1M4, Canada.
Tonya Villafana, Clinical Development, Vaccines & Immune Therapies, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD 20878, USA.
Ann R. Falsey, Rochester Regional HealthFollow
Magdalena E. Sobieszczyk, Division of Infectious Diseases, Department of Medicine, Vagelos College of Physicians and Surgeons, New York-Presbyterian/Columbia University Irving Medical Center, New York, NY 10032, USA.

Department

Infectious Diseases

Document Type

Article

Publication Title

Vaccines

Abstract

A better understanding of the long-term safety, efficacy, and immunogenicity of COVID-19 vaccines is needed. This phase 3, randomized, placebo-controlled study for AZD1222 (ChAdOx1 nCoV-19) primary-series vaccination enrolled 32,450 participants in the USA, Chile, and Peru between August 2020 and January 2021 (NCT04516746). Endpoints included the 2-year follow-up assessment of safety, efficacy, and immunogenicity. After 2 years, no emergent safety signals were observed for AZD1222, and no cases of thrombotic thrombocytopenia syndrome were reported. The assessment of anti-SARS-CoV-2 nucleocapsid antibody titers confirmed the durability of AZD1222 efficacy for up to 6 months, after which infection rates in the AZD1222 group increased over time. Despite this, all-cause and COVID-19-related mortality remained low through the study end, potentially reflecting the post-Omicron decoupling of SARS-CoV-2 infection rates and severe COVID-19 outcomes. Geometric mean titers were elevated for anti-SARS-CoV-2 neutralizing antibodies at the 1-year study visit and the anti-spike antibodies were elevated at year 2, providing further evidence of increasing SARS-CoV-2 infections over long-term follow-up. Overall, this 2-year follow-up of the AZD1222 phase 3 study confirms that the long-term safety profile remains consistent with previous findings and supports the continued need for COVID-19 booster vaccinations due to waning efficacy and humoral immunity.

First Page

883

DOI

10.3390/vaccines12080883

Volume

12

Issue

8

Publication Date

8-3-2024

PubMed ID

39204009

Link to Full Text

Share

COinS