AUTHOR=Canuti Marta , Monti Maria Cristina , Bobbio Chiara , Muscatello Antonio , Muheberimana Toussaint , Baldi Sante Leandro , Blasi Francesco , Canetta Ciro , Costantino Giorgio , Nobili Alessandro , Peyvandi Flora , Tettamanti Mauro , Villa Simone , Aliberti Stefano , Raviglione Mario C. , Gori Andrea , Bandera Alessandra , COVID-19 Network Study Group , Silvano Bosari , Luigia Scudeller , Giuliana Fusetti , Laura Rusconi , Silvia Dell’Orto , Daniele Prati , Luca Valenti , Silvia Giovannelli , Maria Manunta , Giuseppe Lamorte , Francesca Ferarri , Davide Mangioni , Laura Alagna , Giorgio Bozzi , Andrea Lombardi , Riccardo Ungaro , Giuseppe Ancona , Gianluca Zuglian , Matteo Bolis , Nathalie Iannotti , Serena Ludovisi , Agnese Comelli , Giulia Renisi , Simona Biscarini , Valeria Castelli , Emanuele Palomba , Marco Fava , Valeria Fortina , Arianna Liparoti , Andrea Pastena , Carlo Alberto Peri , Paola Saltini , Giulia Viero , Teresa Itri , Valentina Ferroni , Valeria Pastore , Roberta Massafra , Maria Teresa Curri , Alice Rizzo , Stefano Scarpa , Alessandro Giommi , Rosaria Bianco , Grazia Eliana Chitani , Roberta Gualtierotti , Barbara Ferrari , Raffaella Rossio , Nadia Boasi , Erica Pagliaro , Costanza Massimo , Michele De Caro , Andrea Giachi , Nicola Montano , Barbara Vigone , Chiara Bellocchi , Angelica Carandina , Elisa Fiorelli , Valerie Melli , Eleonora Tobaldini , Maura Spotti , Leonardo Terranova , Sofia Misuraca , Alice D’Adda , Silvia Della Fiore , Marta Di Pasquale , Marco Mantero , Martina Contarini , Margherita Ori , Letizia Morlacchi , Valeria Rossetti , Andrea Gramegna , Maria Pappalettera , Mirta Cavallini , Agata Buscemi , Marco Vicenzi , Irena Rota , Monica Solbiati , Ludovico Furlan , Marta Mancarella , Giulia Colombo , Giorgio Colombo , Alice Fanin , Mariele Passarella , Valter Monzani , Angelo Rovellini , Laura Barbetta , Filippo Billi , Christian Folli , Silvia Accordino , Diletta Maira , Cinzia Maria Hu , Irene Motta , Natalia Scaramellini , Anna Ludovica Fracanzani , Rosa Lombardi , Annalisa Cespiati , Matteo Cesari , Tiziano Lucchi , Marco Proietti , Laura Calcaterra , Clara Mandelli , Carlotta Coppola , Arturo Cerizza , Giacomo Grasselli , Alessandro Galazzi , Igor Monti , Alessia Antonella Galbusera TITLE=The role of immune suppression in COVID-19 hospitalization: clinical and epidemiological trends over three years of SARS-CoV-2 epidemic JOURNAL=Frontiers in Medicine VOLUME=10 YEAR=2023 URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2023.1260950 DOI=10.3389/fmed.2023.1260950 ISSN=2296-858X ABSTRACT=

Specific immune suppression types have been associated with a greater risk of severe COVID-19 disease and death. We analyzed data from patients >17 years that were hospitalized for COVID-19 at the “Fondazione IRCCS Ca′ Granda Ospedale Maggiore Policlinico” in Milan (Lombardy, Northern Italy). The study included 1727 SARS-CoV-2-positive patients (1,131 males, median age of 65 years) hospitalized between February 2020 and November 2022. Of these, 321 (18.6%, CI: 16.8–20.4%) had at least one condition defining immune suppression. Immune suppressed subjects were more likely to have other co-morbidities (80.4% vs. 69.8%, p < 0.001) and be vaccinated (37% vs. 12.7%, p < 0.001). We evaluated the contribution of immune suppression to hospitalization during the various stages of the epidemic and investigated whether immune suppression contributed to severe outcomes and death, also considering the vaccination status of the patients. The proportion of immune suppressed patients among all hospitalizations (initially stable at <20%) started to increase around December 2021, and remained high (30–50%). This change coincided with an increase in the proportions of older patients and patients with co-morbidities and with a decrease in the proportion of patients with severe outcomes. Vaccinated patients showed a lower proportion of severe outcomes; among non-vaccinated patients, severe outcomes were more common in immune suppressed individuals. Immune suppression was a significant predictor of severe outcomes, after adjusting for age, sex, co-morbidities, period of hospitalization, and vaccination status (OR: 1.64; 95% CI: 1.23–2.19), while vaccination was a protective factor (OR: 0.31; 95% IC: 0.20–0.47). However, after November 2021, differences in disease outcomes between vaccinated and non-vaccinated groups (for both immune suppressed and immune competent subjects) disappeared. Since December 2021, the spread of the less virulent Omicron variant and an overall higher level of induced and/or natural immunity likely contributed to the observed shift in hospitalized patient characteristics. Nonetheless, vaccination against SARS-CoV-2, likely in combination with naturally acquired immunity, effectively reduced severe outcomes in both immune competent (73.9% vs. 48.2%, p < 0.001) and immune suppressed (66.4% vs. 35.2%, p < 0.001) patients, confirming previous observations about the value of the vaccine in preventing serious disease.