Predominance of influenza virus A(H3N2) 3C.2a1b and A(H1N1)pdm09 6B.1A5A genetic subclades in the WHO European Region, 2018–2019

Angeliki Melidou,Athanasios Kossyvakis,Andrey Komissarov,Anu Haveri,Cherciu Carmen Maria,Ann Machablishvili,Raquel Guiomar,Sonja J Olsen,Alla Mironenko,Francisco Pozo,Conall Mccaughey,Ramona Trebbien,Despo Pieridou,Elena Burtseva,Nina Rodić-Vukmir,Ana Rita Gonçalves,Karoline Bragstad,Vincent Enouf,Maria Koliou,Alexander Nagy,Iryna Demchyshyna,Neli Korsun,Asta Skrickiene,Pasi Penttinen,Altynay Sagymbay,Elena Tichá,Maria Exindari,Cyril Barbezange,Iris Hasibra,Niina Ikonen,Catherine Moore,Isabelle Thomas,Graziella Zahra,Mia Brytting,Dmitriy Pereyaslov,Adam Meijer,Mariana Apostol,Sarah Fitzpatrick,Druc Alina,Cornelia Adlhoch,Emmanuel Robesyn,Catherine Thompson,Maria Rita Castrucci,Guillaume Fournier,Martine Valette,Nataša Berginc,Simona Puzelli,Linda Dunford,Olav Hungnes,Bruno Lina,Svetla Angenova,Pedro Pechirra,Åsa Wiman,Georgia Gioula,Katarina Prosenc,Arthur Löve,Ralf Dürrwald,Inmaculada Casas,Simon Cottrell,Gaukhar Nussupbayeva,Amela Dedeić-Ljubović,Artan Simaku,Vladimir Draženović,Mari Gavashelidze,Sylvie Behillil,Gatis Pakarna,Hannah E Segaloff ,Mónika Rózsa ,Zsolt Molnár ,Mark G O’doherty ,Ron A M Fouchier ,Samantha J Shepherd ,Therese Popow‐Kraupp ,Monika Redlberger‐Fritz ,Guðrún Erna ,Mihaela Lazăr ,Mónica Galiano ,Rory Gunson ,Algirdas Griškevičius ,Martina Havlíčková ,Jackie Maistre Melillo ,Joël Mossong ,Αndreas Mentis ,Natālija Zamjatina ,Edita Staroňová

doi:10.1016/j.vaccine.2020.06.031

Abstract

BackgroundThe 2018/2019 influenza season in the WHO European Region was dominated by influenza A (H1N1)pdm09 and (H3N2) viruses, with very few influenza B viruses detected. MethodsCountries in the European Region reported virus characterization data to The European Surveillance System for weeks 40/2018 to 20/2019. These virus antigenic and genetic characterization and haemagglutinin (HA) sequence data were analysed to describe and assess circulating viruses relative to the 2018/2019 vaccine virus components for the northern hemisphere. ResultsThirty countries reported 4776 viruses characterized genetically and 3311 viruses antigenically. All genetically characterized A(H1N1)pdm09 viruses fell in subclade 6B.1A, of which 90% carried the amino acid substitution S183P in the HA gene. Antigenic data indicated that circulating A(H1N1)pdm09 viruses were similar to the 2018/2019 vaccine virus. Genetic data showed that A(H3N2) viruses mostly fell in clade 3C.2a (75%) and 90% of which were subclade 3C.2a1b. A lower proportion fell in clade 3C.3a (23%) and were antigenically distinct from the vaccine virus. All B/Victoria viruses belonged to clade 1A; 30% carried a double amino acid deletion in HA and were genetically and antigenically similar to the vaccine virus component, while 55% carried a triple amino acid deletion or no deletion in HA; these were antigenically distinct from each other and from the vaccine component. All B/Yamagata viruses belonged to clade 3 and were antigenically similar to the virus component in the quadrivalent vaccine for 2018/2019. ConclusionsA simultaneous circulation of genetically and antigenically diverse A(H3N2) and B/Victoria viruses was observed and represented a challenge to vaccine strain selection.

Highlights

IntroductionRecent years have seen extensive genetic diversification of the haemagglutinin (HA) gene of circulating A (H3N2) viruses with emergence of several subclades [1,2,3]
Influenza viruses are known for their rapid evolution and genetic heterogeneity
In October 2018, the World Health Organization (WHO) Collaborating Centres (WHO CC) at the Francis Crick Institute, London, United Kingdom provided the list of reference viruses for genetic analysis and the The European Surveillance System (TESSy) reporting categories for influenza virus characterization related to the HA gene

Summary

Introduction

Recent years have seen extensive genetic diversification of the haemagglutinin (HA) gene of circulating A (H3N2) viruses with emergence of several subclades [1,2,3]. A (H1N1)pdm viruses have evolved since 2009, more slowly than A(H3N2) viruses, and there are new subclade designations based on the HA gene sequences [4,5,6]. 2017/2018 season [4,5]. Annual vaccine recommendations for the northern and southern hemispheres are based on global epidemiological and virological influenza surveillance data, genetic and antigenic virus characterization data, and the availability of candidate vaccine viruses (CVVs) at the time of the Vaccine Composition Meeting (VCM) in February or September. The 2018/2019 influenza season in the WHO European Region was dominated by influenza.

Methods

Results

Conclusion