Influenza outbreak in patients and healthcare professionals of the Jesenice General Hospital in 2017

Abstract

Background: Influenza is a seasonal viral respiratory disease that occurs during winter months. It is caused by type A and type B influenza viruses. Influenza outbreaks in hospitals are particularly unfavourable as it is the vulnerable population that falls ill. Many complications occur, hospital treatment is prolonged and mortality increases. Healthcare professionals (HP) may also become ill and because of their absenteeism problems arise in the organization of work.

Methods: We present a retrospective cohort study of an influenza outbreak in a General Hospital Jesenice which occurred in a period from 1 January to 16 February 2017. A case definition was as follows: A patient or a healthcare professional (HP) who had signs of influenza-like illness (fever above 37.77 °C with coughing or sore throat) in the absence of other causes of infection and either influenza A or B virus confirmed in the nasopharyngeal swab, or in whom an epidemiological link with a confirmed case (hospitalisation in the same room) was established. Patients who developed these symptoms and signs 72 hours or later after admission were classified as nosocomial cases. We asked the affected HP about demographic data, any previous vaccination against influenza, and their subjective assessment of the severity of the disease.

Results: Of the approximately 250 exposed people, 117 (46.8%) fell ill. The first cases occurred in the internal medicine department, followed by the surgical and nursing departments. The majority of patients were aged 65 and over. We took nasopharyngeal swabs from 74 patients and employees who complied with the definition of a case in the outbreak. Influenza A (87%) or B (13%) was confirmed in 68 (87%) samples. The remaining 49 cases that were not laboratory-confirmed have met the epidemiological link criteria. In the discharge letters of all 13 deceased patients one of the discharge diagnoses was influenza, while in four it was also listed as the direct cause of death. Six patients died of pneumonia that followed the flu. Forty-five patients received oseltamivir, 61 hospitalized patients, and HP took oseltamivir as chemoprophylaxis. The outbreak of influenza had an adverse effect on the work plan of the surgical department - due to the outbreak, the number of elective surgeries decreased and a part of the surgical beds were allocated to the overburdened internist department.

Conclusion: At an early stage of an outbreak in a hospital, a high degree of compliance with preventive measures is required. Patients’ comorbidities and poor general condition contribute to more severe clinical presentation of influenza. Problems in ensuring isolation, non-compliance with the recommendations for personal hygiene of patients, non-vaccination against influenza and poor response of the immune system of elderly patients to vaccination contribute to outbreaks.