Serological protection against influenza and cardiovascular events in cardiac ICU patients during seasonal epidemics
Year: 2026
Type: article
Study design: Observational Study
Abstract: BACKGROUND AND OBJECTIVES: Influenza can be associated with acute cardiovascular events, but the impact of serological protection in high-risk patients admitted to Cardiac Intensive Care Units (C-ICUs) is unknown. This study aimed to analyze previous vaccination rate, level of serological protection and laboratory-confirmed influenza, among patients admitted to C-ICUs during influenza season, and its association with cardiovascular events. METHODS: Prospective multicenter study of all patients admitted to C-ICUs during 2017-2018, 2018-2019, and 2019-2020 influenza seasons. A systematic search for influenza was performed using the Xpert Xpress Flu/RSV assay (Cepheid, Sunnyvale, CA, USA). The seroprotection rate was assessed by analyzing the percentage of patients with antibody titers against influenza ≥1/40, and the intensity of seroprotection by evaluating the geometric mean titers of these antibodies. RESULTS: From 397 patients, 245 (61.7%) reported previous influenza vaccine. A total of 23 patients had laboratory-confirmed influenza (23/397, 5.8%). Overall, the seroprotection rate was significantly higher for influenza A than for B (84.6% vs 37.5%, P < 0.001) and higher in vaccinated than in non-vaccinated group. The highest seroprotection rate and intensity was observed for subtype A(H3N2), followed by A(H1N1)pdm09, B/Victoria, and finally B/Yamagata. Compared unvaccinated patients, those with prior vaccination had lower rates of ST-segment elevation myocardial infarction (28.2% vs 40.8%, P = 0.009), pulmonary embolism (0.8% vs 4.6%, P = 0.014), and severe clinical presentation (53.1% vs 67.1%, P = 0.006). CONCLUSIONS: Serological protection was higher against influenza A than B, especially for the A (H3N2) subtype. ST-segment elevation myocardial infarction, pulmonary embolism, and severe clinical presentation appear to be reduced with influenza vaccination.
Authors: Alicia Galar, Iván Sanz-Muñoz, José María Eiros, Roberto Alonso, Pilar Catalán, Alejandro Cobos, Miriam Juárez, Iago Sousa-Casasnovas, Maricela Valerio, Pablo Antunez-Muiños, Gema Barbeito-Castiñeiras, Silvia Blanco-Alonso, María Dolores Folgueira, José María García-Acuña, Antonio Lalueza, Fernando Lázaro, Esteban Lopez-de-Sa, Lorena Martín, Elena Muñez-Rubio, Francisca Portero, Antonio Ramos-Martínez, María Pilar Romero-Gómez, Sandra Rosillo, Francisco Fernández-Avilés, Manuel Martínez-Sellés, Emilio Bouza, Patricia Munoz
Institutions: Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Hospital Clínico Universitario de Valladolid, Universidad Complutense de Madrid, Centro de Investigación en Red en Enfermedades Cardiovasculares, Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, Complejo Hospitalario Universitario de Santiago, Hospital Universitario Puerta de Hierro Majadahonda, Research Institute Hospital 12 de Octubre, Hospital Universitario 12 De Octubre, Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red Enfermedades Infecciosas, Hospital Universitario La Paz
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,900
OpenAlex ID: W7124899857