Background: Severe acute respiratory illness (SARI) is the main cause of death of infectious origin worldwide, and influenza is of special interest due to the availability of vaccines and specific antiviral therapy.Objective: This work includes 2 objectives: (1).Describe the epidemiological and clinical characteristics of hospitalized patients with severe acute respiratory infection caused by influenza and other respiratory viruses in Cartagena-Colombia.(2).Report the status of immunization and/or vaccination against seasonal influenza.Materials and Methods: This study was conducted in two hospitals located in Cartagena-Colombia, the study population included children and adults admitted to the emergency room with an acute infection process associated with influenza.The identification of infectious agents was done by RT-qPCR and multiplex PCR (FilmArray).Results: 278 patients with potential eligibility for the study were recruited, of which 175 (62.9%) met the inclusion criteria.The most frequently detected viruses were RSV, rhinovirus, and influenza, each with 47.1%, 33.6%, and 17.3% of the cases, respectively.5.6% of the positive cases of influenza were admitted to the ICU and died.The presence of comorbid disease, use of antivirals during hospitalization, and current vaccination was significantly low.Vaccination status for seasonal influenza was most common in <5 years.Several co-infections occurred and some of them were bacterial, Rhinovirus was the most frequent co-infecting viral agent. Conclusion:The active surveillance model is a valuable tool to investigate the impact of respiratory viral diseases in hospitalized patients, providing information that allows the implementation of preventive and control measures.Acute respiratory infections (ARI) are a large group of diseases that affect the upper and lower respiratory system.Higher ARFs are generally not life-threatening, on the contrary, low infections are the fourth leading cause of death in the world with approximately 2.8 million deaths annually [1][2][3].ARIs can be of viral, bacterial or mixed origin.In low-income countries, they are the main