Exposure to avian coronavirus vaccines is associated with increased levels of SARS‐CoV‐2‐cross‐reactive antibodies

• DOI: 10.1111/all.15441
• Publication Date: 2022-07-23T10:06:37Z
• Authors: Ozge Ardicli; K. Tayfun Carli; Pattraporn Satits...; Anita Dreher; Alexia Cusini; Sandra Hutter; David Mirer; Beate Rückert; Hulda R. Jonsdottir; Benjamin Weber; Carlo Cervia; Mubeccel Akdis; Onur Boyman; Alexander Eggel; Marie‐Charlotte B...; Cezmi A. Akdis; Willem van de Veen
• Keywords: 0301 basic medicine; 2403 Immunology; Farmers; SARS-CoV-2; Immunology; Infectious bronchitis virus; COVID-19; 610 Medicine & health; Original Articles; Cross Reactions; Antibodies, Viral; Poultry; 3. Good health; 03 medical and health sciences; 10183 Swiss Institute of Allergy and Asthma Research; Immunoglobulin G; Spike Glycoprotein, Coronavirus; 10033 Clinic for Immunology; 2723 Immunology and Allergy; Immunology and Allergy; Humans; Animals

AbstractBackgroundAlthough avian coronavirus infectious bronchitis virus (IBV) and SARS‐CoV‐2 belong to different genera of the Coronaviridae family, exposure to IBV may result in the development of cross‐reactive antibodies to SARS‐CoV‐2 due to homologous epitopes. We aimed to investigate whether antibody responses to IBV cross‐react with SARS‐CoV‐2 in poultry farm personnel who are occupationally exposed to aerosolized IBV vaccines.MethodsWe analyzed sera from poultry farm personnel, COVID‐19 patients, and pre‐pandemic controls. IgG levels against the SARS‐CoV‐2 antigens S1, RBD, S2, and N and peptides corresponding to the SARS‐CoV‐2 ORF3a, N, and S proteins as well as whole virus antigens of the four major S1‐genotypes 4/91, IS/1494/06, M41, and D274 of IBV were investigated by in‐house ELISAs. Moreover, live‐virus neutralization test (VNT) was performed.ResultsA subgroup of poultry farm personnel showed elevated levels of specific IgG for all tested SARS‐CoV‐2 antigens compared with pre‐pandemic controls. Moreover, poultry farm personnel, COVID‐19 patients, and pre‐pandemic controls showed specific IgG antibodies against IBV strains. These antibody titers were higher in long‐term vaccine implementers. We observed a strong correlation between IBV‐specific IgG and SARS‐CoV‐2 S1‐, RBD‐, S2‐, and N‐specific IgG in poultry farm personnel compared with pre‐pandemic controls and COVID‐19 patients. However, no neutralization was observed for these cross‐reactive antibodies from poultry farm personnel using the VNT.ConclusionWe report here for the first time the detection of cross‐reactive IgG antibodies against SARS‐CoV‐2 antigens in humans exposed to IBV vaccines. These findings may be useful for further studies on the adaptive immunity against COVID‐19.