Dataset Information

Detection of influenza in managed quarantine in Australia and the estimated risk of importation.

ABSTRACT:

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 and used this information to estimate the risk of a case exiting quarantine while still infectious. Influenza-positive samples were sequenced and cases were followed-up to identify transmission clusters. Data on the number of cases and total passengers was used to infer the risk of influenza cases existing quarantine while infectious.

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. Under the quarantine strategy in place at the time, the probability that these cases could initiate influenza outbreaks in Australia neared 0. However, this probability rose as quarantine requirements relaxed.

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 included in the 2022 Southern Hemisphere influenza vaccine. Failing to test quarantined returned travellers for influenza, represents a missed opportunity for enhanced surveillance to better inform public health preparedness.

SUBMITTER: Peck H

PROVIDER: S-EPMC9384744 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature

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Publications

Detection of Influenza in Managed Quarantine in Australia and the Estimated Risk of Importation.

Peck Heidi H Anbumurali Nithila N McMahon Kimberley K Freeman Kevin K Aziz Ammar A Gillespie Leah L Yang Bingyi B Moselen Jean J Deng Yi-Mo YM Cowling Benjamin J BJ Barr Ian G IG Subbarao Kanta K Sullivan Sheena G SG

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 20230201 3

<h4>Background</h4>Influenza circulated at historically low levels during 2020/2021 due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic travel restrictions. In Australia, international arrivals were required to undergo a 14-day hotel quarantine to limit new introduction of SARS-CoV-2.<h4>Methods</h4>We usedtesting data for travelers arriving on repatriation flights to Darwin, Australia, from 3 January 2021 to 11 October 2021 to identify importations of influenza virus in ...[more]

PMID: 35959938

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