Investigation on influenza outbreak in a primary school in Hebei District of Tianjin

Abstract

ObjectiveTo determine the epidemiological characteristics and causes of an influenza outbreak in a primary school in Hebei District， Tianjin， and provide scientific evidence for the prevention and control of influenza outbreaks.MethodsAccording to the Guidelines for the Management of Influenza Like Outbreaks （2012 Edition）， and the throat swabs of patients with influenza were collected for influenza virus detection. Descriptive epidemiological method was used to analyze the data in the outbreak.ResultsA total of 94 cases were identified in this influenza outbreak， with an overall incidence rate of 18.40%. A total of 12 classes were involved. The cases were distributed in Grade 1 （classes 1-9） and Grade 3 （classes 7， 8 and 10）. The highest morbidity rate was 47.50% （19/40） in Class 2 Grade 1， followed by 30.95% （13/42） in Class 1 Grade 1， and the lowest was 2.86% （1/35） in Class 8 Grade 3 and Class 10 Grade 3. The throat swab samples were collected in 11 students， of which 6 tested positive for influenza B virus.ConclusionStudents with influenza were younger， had not been vaccinated against influenza， and attended classes with illness， which led to the further spread of the epidemic. The outbreak has been finally controlled through strengthening morning and afternoon inspection， tracking non-attendant students due to illness， strictly isolating the source of infection， opening windows for ventilation， and conducting preventive disinfection.

Keywords

• influenza
• outbreak
• school
• epidemiological investigation
• epidemic characteristics