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Long-Term Safety and Immunogenicity of AZD1222 (ChAdOx1 nCoV-19): 2-Year Follow-Up from a Phase 3 Study
- Source :
- Vaccines, Vol 12, Iss 8, p 883 (2024)
- Publication Year :
- 2024
- Publisher :
- MDPI AG, 2024.
-
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.
Details
- Language :
- English
- ISSN :
- 2076393X
- Volume :
- 12
- Issue :
- 8
- Database :
- Directory of Open Access Journals
- Journal :
- Vaccines
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.2d77f1972fe84a24aa1bbd148a0543fe
- Document Type :
- article
- Full Text :
- https://doi.org/10.3390/vaccines12080883