World Health Organization Collaborating Centre for Reference and Research on Influenza, Royal Melbourne Hospital, Peter Doherty Institute for Infection and Immunity, Melbourne, Australia.
Department of Infectious Diseases, University of Melbourne, Peter Doherty Institute for Infection and Immunity, Melbourne, Australia.
Clin Infect Dis. 2023 Feb 8;76(3):e1328-e1334. doi: 10.1093/cid/ciac648.
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.
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 into Australia. We 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 were used to infer the risk of influenza cases exiting quarantine while infectious.
Despite very low circulation of influenza globally, 42 cases were identified among 15 026 returned travelers, of which 30 were A(H3N2), 2 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.
Detection of influenza virus infections in repatriated travelers 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. Failure to test quarantined returned travelers for influenza represents a missed opportunity for enhanced surveillance to better inform public health preparedness.
由于严重急性呼吸系统综合征冠状病毒 2（SARS-CoV-2）大流行旅行限制，2020/2021 年期间流感的传播处于历史低位。在澳大利亚，入境人员需接受为期 14 天的酒店隔离，以限制 SARS-CoV-2 的新输入。
我们使用 2021 年 1 月 3 日至 10 月 11 日从达尔文返回澳大利亚的遣返航班旅客的检测数据，以确定流感病毒传入澳大利亚。我们利用这些信息来估计病例在隔离期间仍具有传染性而离开隔离的风险。对流感阳性样本进行测序，并对病例进行随访以确定传播集群。使用病例数和总乘客数的数据来推断具有传染性的流感病例离开隔离的风险。
尽管全球流感的传播非常低，但在 15026 名返回的旅客中发现了 42 例病例，其中 30 例为 A(H3N2)，2 例为 A(H1N1)pdm09，10 例为 B/Victoria。病毒测序数据确定了潜在的飞行中传播，以及旅行前的独立感染。在当时实施的检疫策略下，这些病例在澳大利亚引发流感暴发的可能性接近 0。然而，随着检疫要求的放宽，这种可能性上升。
在遣返旅客中检测到流感病毒感染为澳大利亚提供了一种原本无法获得的流感病毒来源，并使包括在 2022 年南半球流感疫苗中的 A(H3N2)疫苗种子病毒得以开发。未能对隔离的返回旅客进行流感检测是加强监测的错失机会，无法更好地为公共卫生准备提供信息。
