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Characteristics of Seasonal Influenza Virus Activity in a Subtropical City in China, 2013–2019

Background: To optimize seasonal influenza vaccination programs in regions with potentially complicated seasonal patterns, the epidemiological characteristics of seasonal influenza activity in a subtropical city of China were explored. Materials and Methods: Influenza virus data of patients with inf...

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Autores principales: Zhu, Aiqin, Liu, Jianhua, Ye, Chuchu, Yu, Jianxing, Peng, Zhibing, Feng, Luzhao, Wang, Liping, Qin, Ying, Zheng, Yaming, Li, Zhongjie
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7157579/
https://www.ncbi.nlm.nih.gov/pubmed/32121519
http://dx.doi.org/10.3390/vaccines8010108
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author Zhu, Aiqin
Liu, Jianhua
Ye, Chuchu
Yu, Jianxing
Peng, Zhibing
Feng, Luzhao
Wang, Liping
Qin, Ying
Zheng, Yaming
Li, Zhongjie
author_facet Zhu, Aiqin
Liu, Jianhua
Ye, Chuchu
Yu, Jianxing
Peng, Zhibing
Feng, Luzhao
Wang, Liping
Qin, Ying
Zheng, Yaming
Li, Zhongjie
author_sort Zhu, Aiqin
collection PubMed
description Background: To optimize seasonal influenza vaccination programs in regions with potentially complicated seasonal patterns, the epidemiological characteristics of seasonal influenza activity in a subtropical city of China were explored. Materials and Methods: Influenza virus data of patients with influenza-like illness (ILI) during 2013–2019 were collected from two sentinel hospitals in a subtropical region of China, Yichang city. The influenza virus positive rate among sampled ILI cases served as a proxy to estimate influenza seasonal characteristics, including periodicity, duration, peaks, and predominant subtypes/lineages. Epidemiological features of different years, seasons and age groups were analyzed, and vaccine mismatches were identified. Results: In total, 8693 ILI cases were included; 1439 (16.6%) were laboratory-confirmed influenza cases. The influenza A positive rate (10.6%) was higher than the influenza B positive rate (5.9%). There were three influenza circulation patterns in Yichang: (1) annual periodicity (in 2013–2014, 2015–2016 and 2018–2019), (2) semiannual periodicity (in 2014–2015), and (3) year-round periodicity (in 2016–2017 and 2017–2018). Summer epidemics existed in two of the six years and were dominated by influenza A/H3N2. Winter and spring epidemics occurred in five of the six years, and A/H1N1, A/H3N2, B/Victoria, and B/Yamagata were codominant. During the study period, the predominant lineages, B/Victoria in 2015-16 and B/Yamagata in 2017–2018, were both mismatched with the influenza B component of the trivalent vaccine. Children 5–14 years old (26.4%) and individuals over 60 years old (16.9%) had the highest influenza positive rates. Conclusions: The seasonal epidemic period and the predominant subtype/lineage of influenza viruses in Yichang city are complex. Influenza vaccination timing and strategies need to be optimized according to the local features of influenza virus activity.
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spelling pubmed-71575792020-05-01 Characteristics of Seasonal Influenza Virus Activity in a Subtropical City in China, 2013–2019 Zhu, Aiqin Liu, Jianhua Ye, Chuchu Yu, Jianxing Peng, Zhibing Feng, Luzhao Wang, Liping Qin, Ying Zheng, Yaming Li, Zhongjie Vaccines (Basel) Article Background: To optimize seasonal influenza vaccination programs in regions with potentially complicated seasonal patterns, the epidemiological characteristics of seasonal influenza activity in a subtropical city of China were explored. Materials and Methods: Influenza virus data of patients with influenza-like illness (ILI) during 2013–2019 were collected from two sentinel hospitals in a subtropical region of China, Yichang city. The influenza virus positive rate among sampled ILI cases served as a proxy to estimate influenza seasonal characteristics, including periodicity, duration, peaks, and predominant subtypes/lineages. Epidemiological features of different years, seasons and age groups were analyzed, and vaccine mismatches were identified. Results: In total, 8693 ILI cases were included; 1439 (16.6%) were laboratory-confirmed influenza cases. The influenza A positive rate (10.6%) was higher than the influenza B positive rate (5.9%). There were three influenza circulation patterns in Yichang: (1) annual periodicity (in 2013–2014, 2015–2016 and 2018–2019), (2) semiannual periodicity (in 2014–2015), and (3) year-round periodicity (in 2016–2017 and 2017–2018). Summer epidemics existed in two of the six years and were dominated by influenza A/H3N2. Winter and spring epidemics occurred in five of the six years, and A/H1N1, A/H3N2, B/Victoria, and B/Yamagata were codominant. During the study period, the predominant lineages, B/Victoria in 2015-16 and B/Yamagata in 2017–2018, were both mismatched with the influenza B component of the trivalent vaccine. Children 5–14 years old (26.4%) and individuals over 60 years old (16.9%) had the highest influenza positive rates. Conclusions: The seasonal epidemic period and the predominant subtype/lineage of influenza viruses in Yichang city are complex. Influenza vaccination timing and strategies need to be optimized according to the local features of influenza virus activity. MDPI 2020-03-01 /pmc/articles/PMC7157579/ /pubmed/32121519 http://dx.doi.org/10.3390/vaccines8010108 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Zhu, Aiqin
Liu, Jianhua
Ye, Chuchu
Yu, Jianxing
Peng, Zhibing
Feng, Luzhao
Wang, Liping
Qin, Ying
Zheng, Yaming
Li, Zhongjie
Characteristics of Seasonal Influenza Virus Activity in a Subtropical City in China, 2013–2019
title Characteristics of Seasonal Influenza Virus Activity in a Subtropical City in China, 2013–2019
title_full Characteristics of Seasonal Influenza Virus Activity in a Subtropical City in China, 2013–2019
title_fullStr Characteristics of Seasonal Influenza Virus Activity in a Subtropical City in China, 2013–2019
title_full_unstemmed Characteristics of Seasonal Influenza Virus Activity in a Subtropical City in China, 2013–2019
title_short Characteristics of Seasonal Influenza Virus Activity in a Subtropical City in China, 2013–2019
title_sort characteristics of seasonal influenza virus activity in a subtropical city in china, 2013–2019
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7157579/
https://www.ncbi.nlm.nih.gov/pubmed/32121519
http://dx.doi.org/10.3390/vaccines8010108
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