A phase II/III, randomized, double-blind, placebo-controlled trial to evaluate immunogenicity and safety of the Gam-COVID-Vac combined vector vaccine in the prophylactic treatment for SARS-СoV-2 infection in the United Arab Emirates
Background: Long-term efficacy and safety profiles of the various SARS-CoV-2 vaccines were investigated. Current trial aimed to assess the safety and immunogenicity of the Gam-COVID-Vac combined vector vaccine against SARS-CoV-2-induced coronavirus infection up to 6 months post vaccination. Research...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-08-01
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| Series: | Vaccine: X |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590136225000920 |
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| author | Ahmed A.K. AlHammadi Amna H. Alzaabi Haneen B. Choker Ahmed A. Ibrahim Asma Bin Ishaq Ahmed E. Mahboub Reem S. Al Dhaheri Mohamed N. Alzaabi Timothy A. Collyns Gehad ElGhazali Stefan Weber Basel K. Al-Ramadi |
| author_facet | Ahmed A.K. AlHammadi Amna H. Alzaabi Haneen B. Choker Ahmed A. Ibrahim Asma Bin Ishaq Ahmed E. Mahboub Reem S. Al Dhaheri Mohamed N. Alzaabi Timothy A. Collyns Gehad ElGhazali Stefan Weber Basel K. Al-Ramadi |
| author_sort | Ahmed A.K. AlHammadi |
| collection | DOAJ |
| description | Background: Long-term efficacy and safety profiles of the various SARS-CoV-2 vaccines were investigated. Current trial aimed to assess the safety and immunogenicity of the Gam-COVID-Vac combined vector vaccine against SARS-CoV-2-induced coronavirus infection up to 6 months post vaccination. Research design and methods: Participants ≥18 years of age with no prior SARS-COV-2 infection or vaccination were randomized on a 3:1 ratio to receive heterologous recombinant human adenovirus-vectored vaccines or placebo, respectively. Immunogenicity was determined based on quantitative IgG antibodies to viral S and N proteins, virus- neutralizing Abs (VNA), seroconversion rates, and S protein-specific CD4 and CD8 T-cell responses. Results: A total of 990 participants were randomized on a 3:1 ratio to vaccine and placebo groups. Majority of Adverse events were mild-moderate. Two doses of vaccine induced VNA in 100 % of participants on Day 42, with geometric mean ratio (GMR) peaking at 120 days with average 24.14 (p < 0.001). Vaccine group showed a very significant GMR for quantitative IgG to S protein. Seroconversion rates were 90.0 %, 83.7 % and 78.9 % on days 42, 120 and 180 (p < 0.001 compared to placebo). A significant rise in the median of S protein-specific CD4+ and CD8+ T- lymphocytes with a robust IFN-γ response was evident after 28 days compared to baseline. Long-term follow-up demonstrated persistent and significant CD8+ T-cell and IFN-γ responses at 120 days (p = 0.049 and 0.039, respectively) compared to placebo. Conclusions: Gam-COVID-Vac vaccine showed a good safety profile and induced durable humoral and cellular immune responses. The viral-specific CD8+ T-cell response was more durable following vaccination than CD4+ T cell counterpart. Trial Registration: The trial is registered at ClinicalTrials.gov (CT.gov identifier: NCT04656613). |
| format | Article |
| id | doaj-art-19e8f0a32de74bf6bf20f4aa0de75260 |
| institution | DOAJ |
| issn | 2590-1362 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Vaccine: X |
| spelling | doaj-art-19e8f0a32de74bf6bf20f4aa0de752602025-08-20T03:04:51ZengElsevierVaccine: X2590-13622025-08-012510069810.1016/j.jvacx.2025.100698A phase II/III, randomized, double-blind, placebo-controlled trial to evaluate immunogenicity and safety of the Gam-COVID-Vac combined vector vaccine in the prophylactic treatment for SARS-СoV-2 infection in the United Arab EmiratesAhmed A.K. AlHammadi0Amna H. Alzaabi1Haneen B. Choker2Ahmed A. Ibrahim3Asma Bin Ishaq4Ahmed E. Mahboub5Reem S. Al Dhaheri6Mohamed N. Alzaabi7Timothy A. Collyns8Gehad ElGhazali9Stefan Weber10Basel K. Al-Ramadi11Tawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, United Arab Emirates; President, Emirates Infectious Disease Society, Emirates Medical Association, Dubai, United Arab Emirates; Department of Internal Medicine, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Corresponding author at: Tawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA) (Pure Health), Abu Dhabi, United Arab Emirates.Tawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, United Arab EmiratesTawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, United Arab EmiratesTawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, United Arab EmiratesTawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, United Arab EmiratesTawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, United Arab EmiratesTawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, United Arab EmiratesTawam Hospital, Al Ain, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, United Arab EmiratesTawam Hospital, Purelab, Purehealth, Al Ain, Abu Dhabi, United Arab EmiratesSheikh Khalifa Medical City, Purelab, Purehealth, Abu Dhabi, United Arab Emirates; Department of Microbiology, Sheikh Khalifa Medical City, Abu Dhabi, United Arab EmiratesSheikh Khalifa Medical City, Purelab, Purehealth, Abu Dhabi, United Arab Emirates; Department of Microbiology, Sheikh Khalifa Medical City, Abu Dhabi, United Arab EmiratesDepartment of Medical Microbiology & Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Zayed Center for Health Sciences, United Arab Emirates University (UAEU), Al Ain, United Arab Emirates; ASPIRE Precision Medicine Research Institute Abu Dhabi, United Arab Emirates University, Al Ain, United Arab Emirates; Corresponding author at: Department of Medical Microbiology & Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates.Background: Long-term efficacy and safety profiles of the various SARS-CoV-2 vaccines were investigated. Current trial aimed to assess the safety and immunogenicity of the Gam-COVID-Vac combined vector vaccine against SARS-CoV-2-induced coronavirus infection up to 6 months post vaccination. Research design and methods: Participants ≥18 years of age with no prior SARS-COV-2 infection or vaccination were randomized on a 3:1 ratio to receive heterologous recombinant human adenovirus-vectored vaccines or placebo, respectively. Immunogenicity was determined based on quantitative IgG antibodies to viral S and N proteins, virus- neutralizing Abs (VNA), seroconversion rates, and S protein-specific CD4 and CD8 T-cell responses. Results: A total of 990 participants were randomized on a 3:1 ratio to vaccine and placebo groups. Majority of Adverse events were mild-moderate. Two doses of vaccine induced VNA in 100 % of participants on Day 42, with geometric mean ratio (GMR) peaking at 120 days with average 24.14 (p < 0.001). Vaccine group showed a very significant GMR for quantitative IgG to S protein. Seroconversion rates were 90.0 %, 83.7 % and 78.9 % on days 42, 120 and 180 (p < 0.001 compared to placebo). A significant rise in the median of S protein-specific CD4+ and CD8+ T- lymphocytes with a robust IFN-γ response was evident after 28 days compared to baseline. Long-term follow-up demonstrated persistent and significant CD8+ T-cell and IFN-γ responses at 120 days (p = 0.049 and 0.039, respectively) compared to placebo. Conclusions: Gam-COVID-Vac vaccine showed a good safety profile and induced durable humoral and cellular immune responses. The viral-specific CD8+ T-cell response was more durable following vaccination than CD4+ T cell counterpart. Trial Registration: The trial is registered at ClinicalTrials.gov (CT.gov identifier: NCT04656613).http://www.sciencedirect.com/science/article/pii/S2590136225000920COVID-19Randomized control trialVectorAdenoviral vector vaccineSputnik V |
| spellingShingle | Ahmed A.K. AlHammadi Amna H. Alzaabi Haneen B. Choker Ahmed A. Ibrahim Asma Bin Ishaq Ahmed E. Mahboub Reem S. Al Dhaheri Mohamed N. Alzaabi Timothy A. Collyns Gehad ElGhazali Stefan Weber Basel K. Al-Ramadi A phase II/III, randomized, double-blind, placebo-controlled trial to evaluate immunogenicity and safety of the Gam-COVID-Vac combined vector vaccine in the prophylactic treatment for SARS-СoV-2 infection in the United Arab Emirates Vaccine: X COVID-19 Randomized control trial Vector Adenoviral vector vaccine Sputnik V |
| title | A phase II/III, randomized, double-blind, placebo-controlled trial to evaluate immunogenicity and safety of the Gam-COVID-Vac combined vector vaccine in the prophylactic treatment for SARS-СoV-2 infection in the United Arab Emirates |
| title_full | A phase II/III, randomized, double-blind, placebo-controlled trial to evaluate immunogenicity and safety of the Gam-COVID-Vac combined vector vaccine in the prophylactic treatment for SARS-СoV-2 infection in the United Arab Emirates |
| title_fullStr | A phase II/III, randomized, double-blind, placebo-controlled trial to evaluate immunogenicity and safety of the Gam-COVID-Vac combined vector vaccine in the prophylactic treatment for SARS-СoV-2 infection in the United Arab Emirates |
| title_full_unstemmed | A phase II/III, randomized, double-blind, placebo-controlled trial to evaluate immunogenicity and safety of the Gam-COVID-Vac combined vector vaccine in the prophylactic treatment for SARS-СoV-2 infection in the United Arab Emirates |
| title_short | A phase II/III, randomized, double-blind, placebo-controlled trial to evaluate immunogenicity and safety of the Gam-COVID-Vac combined vector vaccine in the prophylactic treatment for SARS-СoV-2 infection in the United Arab Emirates |
| title_sort | phase ii iii randomized double blind placebo controlled trial to evaluate immunogenicity and safety of the gam covid vac combined vector vaccine in the prophylactic treatment for sars сov 2 infection in the united arab emirates |
| topic | COVID-19 Randomized control trial Vector Adenoviral vector vaccine Sputnik V |
| url | http://www.sciencedirect.com/science/article/pii/S2590136225000920 |
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