Abstract
As the first dose of Gam-COVID-Vac, is currently used as a single dose vaccine in some countries, we investigated the immunogenicity of this at 4 weeks (327 naïve individuals). 88.7% seroconverted, with significantly lower seroconversion rates in those over 60 years (p = 0.004) and significantly lower than previously seen with AZD1222 (p = 0.018). 82.6% developed ACE2 receptor blocking antibodies, although levels were significantly lower than following natural infection (p = 0.0009) and a single dose of AZD1222 (p < 0.0001). Similar titres of antibodies were observed to the receptor binding domain of WT, B.1.1.7 and B.1.617.2 compared to AZD1222, while the levels for B.1.351 were significantly higher (p = 0.006) for Gam-COVID-Vac. 30% developed ex vivo IFNγ ELISpot responses (significantly lower than AZD1222), and high frequency of CD107a expressing T cells along with memory B cell responses. Although single dose of Gam-COVID-Vac was highly immunogenic, administration of a second dose is likely to be beneficial.
© 2022. The Author(s).
Publication types
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Comparative Study
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Multicenter Study
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adult
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Aged
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Aged, 80 and over
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Angiotensin-Converting Enzyme 2 / immunology
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Antibodies, Neutralizing / blood*
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Antibodies, Viral / blood*
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Biomarkers / blood
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COVID-19 / immunology
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COVID-19 / prevention & control*
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COVID-19 / virology
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COVID-19 Vaccines / administration & dosage*
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COVID-19 Vaccines / immunology
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ChAdOx1 nCoV-19 / administration & dosage*
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ChAdOx1 nCoV-19 / immunology
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Female
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Humans
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Immunization*
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Immunogenicity, Vaccine*
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Interferon-gamma / metabolism
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Lymphocytes / immunology
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Lymphocytes / metabolism
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Lymphocytes / virology
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Male
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Middle Aged
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SARS-CoV-2 / immunology*
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Seroconversion
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Time Factors
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Treatment Outcome
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Vaccines, Synthetic / administration & dosage*
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Vaccines, Synthetic / immunology
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Young Adult
Substances
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Antibodies, Neutralizing
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Antibodies, Viral
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Biomarkers
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COVID-19 Vaccines
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Gam-COVID-Vac vaccine
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IFNG protein, human
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Vaccines, Synthetic
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Interferon-gamma
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ChAdOx1 nCoV-19
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ACE2 protein, human
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Angiotensin-Converting Enzyme 2