Epidemiological Studies on Infectious Diseases
Analysis on seasonality, age distribution of influenza B cases and matching degree of influenza B vaccine in China, 2011-2019
Wang Qing, Zhang Muli, Qin Ying, Zheng Jiandong, Zhao Hongting, Yang Xiaokun, Li Zhongjie, Peng Zhibin, Feng Luzhao
Published 2020-11-10
Cite as Chin J Epidemiol, 2020, 41(11): 1813-1817. DOI: 10.3760/cma.j.cn112338-20200318-00375
Abstract
ObjectiveTo analyze the seasonality, age distribution of influenza B cases and matching degree of influenza B vaccine in China from 2011 to 2019, and provide evidences for the future surveillance, estimation of disease burden of influenza B, application of quadrivalent vaccines, and development of vaccine strategies.
MethodsThe epidemiological and virological surveillance data of influenza B from week 14 of 2011 to week 13 of 2019 obtained from National Influenza Surveillance Network were used to draw hot spot maps and conduct descriptive statistics to analyze the seasonality and age distribution of influenza B cases. The published antigenicity analysis results from the China Weekly Influenza Report were used to analyze the matching degree between the trivalent vaccine strain and the circulating influenza B strains.
ResultsFrom 2011 to 2019, the incidence of influenza B showed obvious seasonal characteristics, and influenza B virus co-circulated with influenza A virus in six winter-spring seasons, and influenza B virus/Victoria and Yamagata lineages circulated alternately. In some southern provinces, two lineages co-circulated in some southern areas in certain years. The age distribution of influenza B cases was double-peaked, and both lineages had the highest positive rate in age-group 5-15 years, with peaks at age of 10 years; B/Victoria virus had a sub-peak in age-group 25-35 years; B/Yamagata virus had a sub-peak in age-group 55-65 years. Trivalent influenza vaccine strain and influenza B epidemic strains mismatched in 2015-2016 and 2017-2018 seasons, matched in 2011-2012, 2012-2013, 2013-2014, 2014-2015 and 2016-2017 seasons, and moderately matched in 2018-2019 season, but reactivity was low.
ConclusionsInfluenza B mainly occurred in winter-spring season in China, and its intensity was lower than that of influenza A. There was a difference in the age distribution of the cases among different virus strains. Trivalent influenza vaccine strains and influenza B epidemic strains mismatched in several seasons. It is crucial to conduct continuous surveillance of influenza B and disease burden evaluation, improve vaccine immunization strategy, increase influenza vaccination rate to reduce the harm of influenza B in high-risk groups.
Key words:
Influenza B virus; Seasonality; Age distribution; Vaccine match; Vaccine strategy
Contributor Information
Wang Qing
Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease Management, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Zhang Muli
Beijing Chest Hospital, Capital Medical University, Beijing 101149, China
Qin Ying
Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease Management, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Zheng Jiandong
Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease Management, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Zhao Hongting
Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease Management, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Yang Xiaokun
Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease Management, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Li Zhongjie
Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease Management, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Peng Zhibin
Key Laboratory of Surveillance and Early-warning on Infectious Disease, Division of Infectious Disease Management, Chinese Center for Disease Control and Prevention, Beijing 102206, China
Feng Luzhao
School of Population Medicine and Public Health, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
