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. 2017 Feb 23;22(8):30466.
doi: 10.2807/1560-7917.ES.2017.22.8.30466.

Emergence of a novel subclade of influenza A(H3N2) virus in London, December 2016 to January 2017

Heli Harvala  1   2 , Dan Frampton  2 , Paul Grant  1 , Jade Raffle  2 , Ruth Bridget Ferns  2   3 , Zisis Kozlakidis  2 , Paul Kellam  4 , Deenan Pillay  2 , Andrew Hayward  5 , Eleni Nastouli  1   3   6 ; ICONIC Consortium  7
Collaborators, Affiliations

Emergence of a novel subclade of influenza A(H3N2) virus in London, December 2016 to January 2017

Heli Harvala et al. Euro Surveill. .

Erratum in

  • Addendum for Euro Surveill. 2017;22(8).
    Eurosurveillance Editorial Team. Eurosurveillance Editorial Team. Euro Surveill. 2017 Oct;22(40):171005. doi: 10.2807/1560-7917.ES.2017.22.40.171005. Euro Surveill. 2017. PMID: 29019318 Free PMC article. No abstract available.

Abstract

We report the molecular investigations of a large influenza A(H3N2) outbreak, in a season characterised by sharp increase in influenza admissions since December 2016. Analysis of haemagglutinin (HA) sequences demonstrated co-circulation of multiple clades (3C.3a, 3C.2a and 3C.2a1). Most variants fell into a novel subclade (proposed as 3C.2a2); they possessed four unique amino acid substitutions in the HA protein and loss of a potential glycosylation site. These changes potentially modify the H3N2 strain antigenicity.

Keywords: influenza; molecular; next generation sequencing; outbreak.

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Conflict of interest statement

Conflict of interest: None declared.

Figures

Figure 1
Figure 1
Percentage of positive respiratory samples for given viruses, and total number of respiratory samples tested per week, at the Department of Clinical Virology, University College of London Hospital, 19 September 2016–30 January 2017 (n=1,690 samples)
Figure 2
Figure 2
Number (A) and age distribution (B) of influenza A(H3N2)-positive patients diagnosed at the University College of London Hospitals, 16 December 2016–24 January 2017 (n=253 patients)
Figure 3
Figure 3
Phylogenetic tree of the haemagglutinin gene sequences of virus strains recovered in this study using reference viruses for the different phylogenetic influenza A(H3N2)clades (n = 103 sequences)
Figure 4
Figure 4
Schematic diagram demonstrating the shared haemagglutinin (HA) amino acid changes between clades 3c, 3C.2, 3C.2a, 3C.2a1 and 3C.2a2 based on HA1 and HA2 numbering
See this image and copyright information in PMC

References

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