Impact of Preexisting Anti-Adenovirus 26 Humoral Immunity on Immunogenicity of the Ad26.COV2.S Coronavirus Disease 2019 Vaccine.

Le Gars, Mathieu; Sadoff, Jerald; Struyf, Frank; Heerwegh, Dirk; Truyers, Carla; Hendriks, Jenny; Gray, Glenda; Grinsztejn, Beatriz et al. · J Infect Dis · 2022

prospective_cohort · Level II

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Abstract

This secondary analysis of the phase 3 ENSEMBLE trial (NCT04505722) assessed the impact of preexisting humoral immunity to adenovirus 26 (Ad26) on the immunogenicity of Ad26.COV2.S-elicited severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody levels in 380 participants in Brazil, South Africa, and the United States. Among those vaccinated in Brazil and South Africa, 31% and 66%, respectively, had prevaccination serum-neutralizing activity against Ad26, with little preexisting immunity detected in the United States. Vaccine recipients in each country had similar postvaccination spike (S) protein-binding antibody levels, indicating that baseline immunity to Ad26 has no clear impact on vaccine-induced immune responses.

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