소아 인플루에자 A, B형의 최근 유행양상및 그들 간의 비교

Abstract

Purpose: There was no recent study for epidemiological features of childhood influenza by antigenic type. This study was done to know them and their differences in the same types and between two types (A, B) by time period. Methods: I collected the epidemiological and demographic informations of influenza patients who had visited and been diagnosed at the Department of Pediatrics, Yogin Severance Hospital from January 2014 to May 2016. Influenza infection was decided with rapid antigen assay. They were classified by its antigenic type, year and month. Their demographic and epidemiological features were collected, investigated and compared with each other with parameters mentioned above. Results: There were 335 cases for type A and 244 cases for Type B. Their epidemic began on January and fade away on March in type A and on March or April in type B. Peak occurrences of each type were different by year. The accumulative monthly composition rates of type B were increased continuously from January (7.4%) to March (87.5%) ( P <0.001). The transition of major antigenic type by month was more prominent in 2016 than in 2014 or 2015. Their mean age for type A and type B were 6.1±3.9 years old and 7.0±4.0 years old ( P =0.007), respectively. Type A showed male predominance (1.3:1) but type B did not (1.0:1). Annual ages were only different between two types in 2016 (5.6±3.6 years old for type A and 7.2±4.1 years old for type B; P =0.036), but not in the both same types by year. Their age change patterns was different. Both types showed increasing pattern for accumulative monthly age, but no significant difference among them. Their monthly ages were significantly different in 2016 between on January (4.5±4.3 years old) and on February (6.1±3.7 years old) for type A ( P =0.015) as well as between on February (5.8±3.5 years old) and on March (7.5±4.1 years old; P =0.046) or April (7.9±4.2 years old; P =0.038) for type B, but not between two types or in other years. Annual male to female ratios were different between them in 2016 (1.7:1 for type A and 1.0:1 for type B; P =0.047), but not in other years and in the same types. Accumulative monthly sex ratios were not different among them. Monthly sex ratios of each year was only different between them on February in 2016 (1.8:1 for type A and 0.7:1 for type B; P =0.037). Conclusion: The update epidemiological features of influenza were different between two antigenic types as well as in the same type cases in terms of year and month , especially in 2016. Monitoring of influenza epidemic by type should be carried on and the clinical implication of epidemiological changes be investigated.