Age-dependent influenza infection patterns and subtype circulation in Denmark, in seasons 2015/16 to 2021/22

Author:

Emborg Hanne-Dorthe1ORCID,Bolt Botnen Amanda2,Nielsen Jens1,Vestergaard Lasse S.1,Lomholt Frederikke Kristensen1,Munkstrup Charlotte1,Møller Karina Lauenborg3,Kjelsø Charlotte1,Rasmussen Steen Hulthin3,Trebbien Ramona2

Affiliation:

1. Department of Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Denmark

2. National Influenza Centre for WHO, Department of Virus and Microbiological Special Diagnostics, Statens Serum Institut, Denmark

3. Division of Infectious Disease Preparedness, Statens Serum Institut, Denmark

Abstract

Background Influenza was almost absent for 2 years following the implementation of strict public health measures to prevent the spread of SARS-CoV-2. The consequence of this on infections in different age groups is not yet known. Aim To describe the age groups infected with the influenza virus in 2021/22, the first post-pandemic influenza season in Denmark, compared with the previous six seasons, and subtypes circulating therein. Methods Infection and hospitalisation incidences per season and age group were estimated from data in Danish registries. Influenza virus subtypes and lineages were available from samples sent to the National Influenza Centre at Statens Serum Institut. Results Test incidence followed a similar pattern in all seasons, being highest in 0–1-year-olds and individuals over 75 years, and lowest in 7–14-year-olds and young people 15 years to late twenties. When the influenza A virus subtypes A(H3N2) and A(H1N1)pdm09 co-circulated in seasons 2015/16 and 2017/18 to 2019/20, the proportion of A(H1N1)pdm09 was higher in 0–1-year-olds and lower in the over 85-year-olds  compared with the overall proportion of A(H1N1)pdm09 in these seasons. The proportion of A(H3N2) was higher in the over 85 years age group compared with the overall proportion of A(H3N2). The 2016/17 and 2021/22 seasons were dominated by A(H3N2) but differed in age-specific trends, with the over 85 years age group initiating the 2016/17 season, while the 2021/22 season was initiated by the 15–25-year-olds, followed by 7–14-year-olds. Conclusion The 2021/22 influenza season had a different age distribution compared with pre-COVID-19 pandemic seasons.

Publisher

European Centre for Disease Control and Prevention (ECDC)

Reference32 articles.

1. World Health Organization (WHO). Comparison of number of influenza detections by subtype. Geneva: WHO. [Accessed: 4 May 2023]. Available from: https://app.powerbi.com/view?r=eyJrIjoiZTIxMzAwMzYtZWE4NC00YTU2LWE3MTUtMTI0OGY1ZjQyMWViIiwidCI6ImY2MTBjMGI3LWJkMjQtNGIzOS04MTBiLTNkYzI4MGFmYjU5MCIsImMiOjh9

2. Abrupt termination of the 2019/20 influenza season following preventive measures against COVID-19 in Denmark, Norway and Sweden.;Emborg;Euro Surveill,2021

3. A late sharp increase in influenza detections and low interim vaccine effectiveness against the circulating A(H3N2) strain, Denmark, 2021/22 influenza season up to 25 March 2022.;Emborg;Euro Surveill,2022

4. COVID-19 preventive measures coincided with a marked decline in other infectious diseases in Denmark, spring 2020.;Nielsen;Epidemiol Infect,2022

5. Impact of non-pharmaceutical interventions targeted at COVID-19 pandemic on influenza burden - a systematic review.;Fricke;J Infect,2021

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3