Association of Influenza Vaccination and Prognosis in Patients Testing Positive to SARS-CoV-2 Swab Test: A Large-Scale Italian Multi-Database Cohort Study
Marco Massari,
Stefania Spila-Alegiani,
Massimo Fabiani,
Valeria Belleudi,
Gianluca Trifirò,
Ursula Kirchmayer,
Francesca Romana Poggi,
Pamela Mancuso,
Francesca Menniti-Ippolito,
Rosa Gini,
Claudia Bartolini,
Olivia Leoni,
Michele Ercolanoni,
Filippo Da-Re,
Stefano Guzzinati,
Nicoletta Luxi,
Flavia Riccardo,
Paolo Giorgi-Rossi
Affiliations
Marco Massari
Pharmacoepidemiology Unit, National Centre for Drug Research and Evaluation (CNRVF), Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
Stefania Spila-Alegiani
Pharmacoepidemiology Unit, National Centre for Drug Research and Evaluation (CNRVF), Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
Massimo Fabiani
Department of Infectious Diseases (DMI), Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
Valeria Belleudi
Department of Epidemiology ASL Roma 1, Lazio Regional Health Service, Via Cristoforo Colombo 112, 00147 Rome, Italy
Gianluca Trifirò
Department of Diagnostics and Public Health, University of Verona, Piazzale L.A. Scuro 3, 37134 Verona, Italy
Ursula Kirchmayer
Department of Epidemiology ASL Roma 1, Lazio Regional Health Service, Via Cristoforo Colombo 112, 00147 Rome, Italy
Francesca Romana Poggi
Department of Epidemiology ASL Roma 1, Lazio Regional Health Service, Via Cristoforo Colombo 112, 00147 Rome, Italy
Pamela Mancuso
Epidemiology Unit, Azienda Unità Sanitaria Locale-IRCCS di Reggio Emilia, Via Giovanni Amendola 2, 42122 Reggio Emilia, Italy
Francesca Menniti-Ippolito
Pharmacoepidemiology Unit, National Centre for Drug Research and Evaluation (CNRVF), Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
Rosa Gini
Agenzia Regionale di Sanità della Toscana, Via Pietro Dazzi 1, 50141 Florence, Italy
Claudia Bartolini
Agenzia Regionale di Sanità della Toscana, Via Pietro Dazzi 1, 50141 Florence, Italy
Olivia Leoni
Department of Health of Lombardy Region, Epidemiology Observatory, Piazza Città di Lombardia 1, 20124 Milan, Italy
Michele Ercolanoni
Department of Health of Lombardy Region, Epidemiology Observatory, Piazza Città di Lombardia 1, 20124 Milan, Italy
Filippo Da-Re
Regional Directorate of Prevention, Food Safety, Veterinary Public Health, Regione del Veneto, Rio Novo-Dorsoduro 3493, 30123 Venice, Italy
Stefano Guzzinati
Azienda Zero, Regione del Veneto, Passaggio Luigi Gaudenzio, 1, 35131 Padova, Italy
Nicoletta Luxi
Department BIOMORF, University of Messina, Piazza Pugliatti 1, 98122 Messina, Italy
Flavia Riccardo
Department of Infectious Diseases (DMI), Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
Paolo Giorgi-Rossi
Epidemiology Unit, Azienda Unità Sanitaria Locale-IRCCS di Reggio Emilia, Via Giovanni Amendola 2, 42122 Reggio Emilia, Italy
To investigate the association of the 2019–2020 influenza vaccine with prognosis of patients positive for SARS-CoV-2A, a large multi-database cohort study was conducted in four Italian regions (i.e., Lazio, Lombardy, Veneto, and Tuscany) and the Reggio Emilia province (Emilia-Romagna). More than 21 million adults were residing in the study area (42% of the population). We included 115,945 COVID-19 cases diagnosed during the first wave of the pandemic (February–May, 2020); 34.6% of these had been vaccinated against influenza. Three outcomes were considered: hospitalization, death, and intensive care unit (ICU) admission/death. The adjusted relative risk (RR) of being hospitalized in the vaccinated group when compared with the non-vaccinated group was 0.87 (95% CI: 0.86–0.88). This reduction in risk was not confirmed for death (RR = 1.04; 95% CI: 1.01–1.06), or for the combined outcome of ICU admission or death. In conclusion, our study, conducted on the vast majority of the population during the first wave of the pandemic in Italy, showed a 13% statistically significant reduction in the risk of hospitalization in some geographical areas and in the younger population. No impact of seasonal influenza vaccination on COVID-19 prognosis in terms of death and death or ICU admission was estimated.
