Vaccine-induced spike- and nucleocapsid-specific cellular responses maintain potent cross-reactivity to SARS-CoV-2 Delta and Omicron variants.

Cell-mediated immunity may contribute to providing protection against SARS-CoV-2 and its variants of concern (VOC). We developed COH04S1, a synthetic multiantigen modified vaccinia Ankara (MVA)-based COVID-19 vaccine that stimulated potent spike (S) and nucleocapsid (N) antigen-specific humoral and cellular immunity in a phase 1 clinical trial in healthy adults. Here, we show that individuals vaccinated with COH04S1 or mRNA vaccine BNT162b2 maintain robust cross-reactive cellular immunity for six or more months post-vaccination. Although neutralizing antibodies induced in COH04S1- and BNT162b2-vaccinees showed reduced activity against Delta and Omicron variants compared to ancestral SARS-CoV-2, S-specific T cells elicited in both COH04S1- and BNT162b2-vaccinees and N-specific T cells elicited in COH04S1-vaccinees demonstrated potent and equivalent cross-reactivity against ancestral SARS-CoV-2 and the major VOC. These results suggest that vaccine-induced T cells to S and N antigens may constitute a critical second line of defense to provide long-term protection against SARS-CoV-2 VOC.

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© 2022 The Author(s).

Déclaration de conflit d'intérêts

While unknown whether the publication of this report will aid in receiving grants and contracts, it is possible that this publication will be of benefit to the City of Hope (COH). COH had no role in the conceptualization, design, data collection, analysis, decision to publish, or preparation of the article. DJD and FW are co-inventors on a patent application covering the design and construction of the synthetic MVA platform (PCT/US2021/016,247). DJD, FW, and FC are co-inventors on a patent application covering the development of a COVID-19 vaccine (PCT/US2021/032,821). DJD is a consultant for GeoVax. All other authors declare no competing interests. GeoVax Labs Inc. has taken a worldwide exclusive license for COH04S1 under the name of GEO-CM04S1.