biostudies-literatureUnknownReinig SNIAID NIH HHSDengue virus is a mosquito transmitted flavivirus that cause inapparent or mild disease but can also cause severe hemorrhagic fever in humans. Cross-reactive IgG antibodies can cause under specific conditions antibody dependent enhancement (ADE) of the infection via Fc-receptor interaction. Antibodies from SARS-CoV-2 (anti-S) causing COVID-19 disease can also cross-react against the dengue envelope (anti-E). We therefore investigated the antibody profile of these cross-reactive antibodies and their ability to induce ADE. We found that the cross-reactive anti-E in COVID-19 vaccinated are dominated by IgM/A while, anti-S from vaccinated or anti-E from dengue infected patients have an IgG1 dominated antibody profile. The low-level anti-E IgG from COVID-19 vaccinated are dominated by low Fc-afmedRxiv : the preprint server for health sciences2025.05.23.25328123https://www.ebi.ac.uk/biostudies/studies/S-EPMC12258759biostudies-literatureCOVID-19 Vaccination Induces Cross-Reactive Dengue Antibodies with Altered Isotype Profiles and In Vitro ADE.PMC12258759U01 AI151698Tsai CYHsiung KCIto ELin SMChen PKReinig SHuang SYLee IKKuo CShih SRfalseCOVID-19 Vaccination Induces Cross-Reactive Dengue Antibodies with Altered Isotype Profiles and In Vitro ADE.Dengue virus is a mosquito transmitted flavivirus that cause inapparent or mild disease but can also cause severe hemorrhagic fever in humans. Cross-reactive IgG antibodies can cause under specific conditions antibody dependent enhancement (ADE) of the infection via Fc-receptor interaction. Antibodies from SARS-CoV-2 (anti-S) causing COVID-19 disease can also cross-react against the dengue envelope (anti-E). We therefore investigated the antibody profile of these cross-reactive antibodies and their ability to induce ADE. We found that the cross-reactive anti-E in COVID-19 vaccinated are dominated by IgM/A while, anti-S from vaccinated or anti-E from dengue infected patients have an IgG1 dominated antibody profile. The low-level anti-E IgG from COVID-19 vaccinated are dominated by low Fc-af2025-01-01T00:00:00Z2025 May2026-06-29T03:21:22.576Z2025-08-13T03:04:34.459ZS-EPMC122587594066128810.1101/2025.05.23.25328123