Incidence of Influenza Among Childhood Cancer Survivors in South Korea: A Population-based Retrospective Analysis.

BACKGROUND/AIM: We quantified the incidence, and identified risk factors for influenza infection among childhood cancer survivors in South Korea, an at-risk population. PATIENTS AND METHODS: Nationwide health insurance claims data were used to assess the frequency of influenza among childhood cancer survivors (aged <20 years) diagnosed between January 2009 and April 2016. A multivariable logistic regression was constructed to identify risk factors for influenza. RESULTS: Of 6,457 children cancer survivors, 1,704 (27.0%) were diagnosed with influenza. Influenza was common in children <5 years old and infections were highest between late October and April. Over 60% of influenza treatment claims came from private clinics. Risk factors for influenza included age <9 years. CONCLUSION: Childhood cancer survivors are particularly at-risk for influenza infection during the traditional influenza season. Identifying risks for influenza infection will help to establish countermeasures for reducing the influenza infections in at-risk cancer surviving children.