Evaluating the effectiveness of influenza vaccines in reducing COVID-19 in healthcare workers: a historical cohort study Evaluación de la efectividad de las vacunas contra la gripe en la reducción del riesgo de COVID-19 en trabajadores de la salud: estudio de cohorte histórico
VacciMonitor, vol.35, 2026 (Scopus)
- Publication Type: Article / Article
- Volume: 35
- Publication Date: 2026
- Journal Name: VacciMonitor
- Journal Indexes: Scopus, EMBASE, Directory of Open Access Journals, Academic Search Ultimate (EBSCO), Biomedical Reference Collection: Corporate Edition (EBSCO)
- Keywords: COVID-19, influenza, SARS-CoV-2, vaccination
- Kocaeli University Affiliated: Yes
Abstract
COVID-19 will remain present, therefore specific prevention, diagnosis, and treatment strategies similar to those used for other diseases will be required. There is ongoing concerns about the future of SARS-CoV-2 due to mutations and the emergence of new strains. This study aimed to evaluate the effectiveness of the influenza vaccine in reducing COVID-19 incidence among healthcare workers. Participants were divided into two groups: those who had received the influenza vaccine and those who had not. The efficacy of the influenza vaccine against COVID-19 was assessed over 3 months in all subjects. The diagnosis of COVID-19 was established using a computed tomography scan and RT-PCR testing. A total of 252 individuals participated in this study, with a mean age of 33.90 ± 7.58 years (range: 20 - 59). Of the total, 101 (40.08 %) were male, and 151 (59.92 %) were female. Our findings demonstrate that the prevalence of COVID-19 infection among medical staff who received the influenza vaccination was significantly lower (80.1 % vs 45.0 %) (P < 0.001). The duration of COVID-19 was significantly shorter for vaccine recipients compared to non-recipients, at 2 weeks or less (72.5 % vs 26.6 %) (P < 0.001). The vaccinated cohort had a 55 % lower likelihood of contracting COVID-19 than the unvaccinated cohort (relative risk, RR: 0.45; 95 % confidence interval, CI: 0.34 - 0.59). Further analysis revealed that in severe COVID-19 cases necessitating hospitalization, there is no substantial difference between vaccinated and unvaccinated patients (P=0.2). A recent survey suggested that the influenza vaccine may help improve COVID-19 management. The cytokine profile of the examined patient before the influenza vaccine is the ideal selection.