Antigenic drift and epidemiological severity of seasonal influenza in Canada

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DOI

https://doi.org/10.1038/s41598-022-19996-7

Language of the publication
English
Date
2022-09-17
Type
Article
Author(s)
  • Chen, Zishu
  • Bancej, Christina
  • Lee, Liza
  • Champredon, David
Publisher
Nature

Abstract

Seasonal influenza epidemics circulate globally every year with varying levels of severity. One of the major drivers of this seasonal variation is thought to be the antigenic drift of influenza viruses, resulting from the accumulation of mutations in viral surface proteins. In this study, we aimed to investigate the association between the genetic drift of seasonal influenza viruses (A/H1N1, A/H3N2 and B) and the epidemiological severity of seasonal epidemics within a Canadian context. We obtained hemagglutinin protein sequences collected in Canada between the 2006/2007 and 2019/2020 flu seasons from GISAID and calculated Hamming distances in a sequence-based approach to estimating inter-seasonal antigenic differences. We also gathered epidemiological data on cases, hospitalizations and deaths from national surveillance systems and other official sources, as well as vaccine effectiveness estimates to address potential effect modification. These aggregate measures of disease severity were integrated into a single seasonal severity index. We performed linear regressions of our severity index with respect to the inter-seasonal antigenic distances, controlling for vaccine effectiveness. We did not find any evidence of a statistical relationship between antigenic distance and seasonal influenza severity in Canada. Future studies may need to account for additional factors, such as co-circulation of other respiratory pathogens, population imprinting, cohort effects and environmental parameters, which may drive seasonal influenza severity.

Plain language summary

One of the major drivers of this seasonal variation is thought to be the antigenic drift of influenza viruses, resulting from the accumulation of mutations in viral surface proteins. In this study, we aimed to investigate the association between the genetic drift of seasonal influenza viruses (A/H1N1, A/H3N2 and B) and the epidemiological severity of seasonal epidemics within a Canadian context. We obtained hemagglutinin protein sequences collected in Canada between the 2006/2007 and 2019/2020 flu seasons from GISAID and calculated Hamming distances in a sequence-based approach to estimating inter-seasonal antigenic differences. We also gathered epidemiological data on cases, hospitalizations and deaths from national surveillance systems and other official sources, as well as vaccine effectiveness estimates to address potential effect modification. These aggregate measures of disease severity were integrated into a single seasonal severity index. We performed linear regressions of our severity index with respect to the inter-seasonal antigenic distances, controlling for vaccine effectiveness. We did not find any evidence of a statistical relationship between antigenic distance and seasonal influenza severity in Canada.

Subject

  • Health

Keywords

  • Antigenic Drift and Shift,
  • Antigens,
  • Canada / epidemiology,
  • Hemagglutinins,
  • Humans,
  • Influenza A Virus, H1N1 Subtype* / genetics,
  • Influenza A Virus, H3N2 Subtype / genetics,
  • Influenza Vaccines*,
  • Influenza, Human*,
  • Membrane Proteins / genetics,
  • Seasons

Rights

Peer review

Yes

Open access level

Gold

Article

Journal title
Scientific Reports
Journal volume
12
Article number
15625 (2022)

Citation(s)

Chen Z, Bancej C, Lee L, Champredon D. Antigenic drift and epidemiological severity of seasonal influenza in Canada. Scientific Reports. 2022;12(1). doi:https://doi.org/10.1038/s41598-022-19996-7

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Communicable diseases

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