Poster Presentation Asia-Pacific Vaccine and Immunotherapy Congress 2023

Utilising managed quarantine in Australia for influenza virus characterisation and vaccine strain selection (#155)

Heidi A Peck 1 , Nithila Anbumurali 2 , Kimberley McMahon 3 , Kevin Freeman 4 , Ammar Aziz 1 , Leah Gillespie 1 , Bingyi Yang 5 , Jean Moselen 1 , Yi-Mo Deng 1 , Benjamin J Cowling 5 , Ian G Barr 1 , Kanta Subbarao 1 2 , Sheena Sullivan 1 2
  1. WHO Collaborating Centre for Influenza, Melbourne, VIC, Australia
  2. Department of Microbiology and immunology, University of Melbourne, Melbourne, Australia
  3. Public Health Unit, Centre for Disease Control, Casuarina, Northern Territory, Australia
  4. Serology and Molecular Biology, Territory Pathology, Darwin, Northern Territory, Australia
  5. WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, University of Hong Kong, Hong Kong, SAR, China

Background

Influenza circulated at historically-low levels during 2020 and 2021 due to COVID-19 pandemic travel restrictions. In Australia, international arrivals to Australia were required to undertake 14 days hotel quarantine to limit new introduction of SARS-CoV-2 virus.

 

Methods

We used routine testing data for travellers arriving on repatriation flights to Darwin, Australia from 3 January to 11 October 2021 to identify importations of influenza virus into Australia.Viruses were characterised both genetically and antigenically. A selection of viruses were also propagated in embryonated eggs and a qualified cell-line for vaccine development.

 

Results

Despite very low circulation of influenza globally, 42 cases were identified among 15,026 returned travellers, of which 30 were A(H3N2), two were A(H1N1)pdm09 and 10 were B/Victoria. Virus sequencing data identified potential in-flight transmission, as well as independent infections prior to travel.

 

Conclusions

Detection of influenza virus infections in repatriated travellers provided a source of influenza viruses otherwise unavailable and enabled development of the A(H3N2) vaccine seed viruses that included in the eventual 2022 Southern Hemisphere influenza vaccine virus, A/Darwin/6/2021.