Epidemiological dynamics of influenza B virus across multiple seasons in Kenya and Uganda inferred from sequence data, 2010–2021
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Background
Influenza B virus (IBV) contributes significantly to morbidity and mortality during Influenza seasons annually. However, IBV genomic surveillance occurs unevenly across the globe, particularly within the African region, obscuring its epidemiology. This study aims to elucidate the epidemiological dynamics of IBV in Kenya and Uganda between 2010 and 2022.
Methods
In this study, 83 near complete IBV genomes circulating in Kenya and Uganda between 2010 and 2022 were generated through Oxford Nanopore Technologies sequencing (ONT). Publicly available IBV datasets were incorporated to evaluate the public context of these genomes. Further evolutionary dynamics analysis investigated the antigenic mutation, reassortment and glycosylation patterns of IBVs circulating in Kenya and Uganda within this period.
Results
Alternating IBV lineage predominance and clade turnover was observed consistent with global patterns. No B/Yamagata strains were detected at the study sites after 2019. Multiple B/Victoria clade/subclades (V1A, V1A.3, V1A.3a, V1A.3a.2) and B/Yamagata clades (Y2 and Y3) were identified with no inter-lineage reassortments observed. Over time, the clades/subclades appeared to diversify through the accumulation of amino acid changes along the hemagglutinin (HA) segment backbone, especially within the known antigenic sites. Local outbreak strains appeared to be putatively introduced from both within and outside Africa.
Conclusions
The congruence of local and global strains in circulating lineages and amino acid changes suggests potential effectiveness of vaccines recommended for the Northern and Southern Hemispheres in East Africa.
Influenza B virus (IBV) contributes significantly to morbidity and mortality during Influenza seasons annually. However, IBV genomic surveillance occurs unevenly across the globe, particularly within the African region, obscuring its epidemiology. This study aims to elucidate the epidemiological dynamics of IBV in Kenya and Uganda between 2010 and 2022.
Methods
In this study, 83 near complete IBV genomes circulating in Kenya and Uganda between 2010 and 2022 were generated through Oxford Nanopore Technologies sequencing (ONT). Publicly available IBV datasets were incorporated to evaluate the public context of these genomes. Further evolutionary dynamics analysis investigated the antigenic mutation, reassortment and glycosylation patterns of IBVs circulating in Kenya and Uganda within this period.
Results
Alternating IBV lineage predominance and clade turnover was observed consistent with global patterns. No B/Yamagata strains were detected at the study sites after 2019. Multiple B/Victoria clade/subclades (V1A, V1A.3, V1A.3a, V1A.3a.2) and B/Yamagata clades (Y2 and Y3) were identified with no inter-lineage reassortments observed. Over time, the clades/subclades appeared to diversify through the accumulation of amino acid changes along the hemagglutinin (HA) segment backbone, especially within the known antigenic sites. Local outbreak strains appeared to be putatively introduced from both within and outside Africa.
Conclusions
The congruence of local and global strains in circulating lineages and amino acid changes suggests potential effectiveness of vaccines recommended for the Northern and Southern Hemispheres in East Africa.
Date Issued
2025-08-29
Date Acceptance
2025-07-24
Citation
BMC Infectious Diseases, 2025, 25
ISSN
1471-2334
Publisher
BMC
Journal / Book Title
BMC Infectious Diseases
Volume
25
Copyright Statement
© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
Publication Status
Published
Article Number
1080
Date Publish Online
2025-08-29