AUTHOR=Torre Davide , Orlandi Chiara , Conti Ilaria , Barocci Simone , Carlotti Eugenio , Magnani Mauro , Casabianca Anna , Stefanetti Giuseppe TITLE=Analysis of humoral and cellular immune activation up to 21 months after heterologous and homologous COVID-19 vaccination JOURNAL=Frontiers in Immunology VOLUME=Volume 16 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1579163 DOI=10.3389/fimmu.2025.1579163 ISSN=1664-3224