Marsh Celeste K, Sheppeard Vicky, Tobin Sean, Gilmour Robin, Andrews Ross M
Australian Department of Health, Canberra, ACT.
NSW Health, Sydney, NSW.
Med J Aust. 2022 Jan 17;216(1):33-38. doi: 10.5694/mja2.51266. Epub 2021 Sep 21.
To assess the extent to which the 2018-19 New South Wales summer influenza epidemic was associated with overseas or domestic travel and with seasonal influenza vaccination status.
DESIGN, SETTING: Unmatched case-control study, based on an online survey distributed from the NSW Notifiable Conditions Information Management System (NCIMS) to people for whom mobile phone numbers were available.
A case was defined as a person with notified laboratory-confirmed influenza with onset of illness between 1 December 2018 and 21 March 2019. People with notified pertussis infections (confirmed or probable) were selected as controls.
Notified influenza infection, by travel and contact with unwell overseas travellers in the week before onset of illness and seasonal influenza vaccination status (as the primary exposures).
Valid survey responses were provided by 648 of 2806 invited people with notified influenza (23%) and 257 of 796 invited people with notified pertussis (32%). The demographic characteristics of the respondents were similar to those of the source population (7251 cases, 2254 controls). During the first two months of the summer of 2018-19, notified influenza was more likely for people who had travelled overseas or had contact with an ill overseas traveller in the week before symptom onset (adjusted OR [aOR], 6.99; 95% CI, 3.59-13.6), but not during the second two months (aOR, 1.63; 95% CI, 0.79-3.35). Influenza vaccination status was not associated with the likelihood of notified influenza.
Travel-related factors were early drivers of the 2018-19 NSW summer influenza epidemic; local transmission sustained the outbreak despite unfavourable conditions later in summer. Our findings prompted re-evaluation of recommendations for pre-travel vaccination in NSW. The role of travel in out-of-season influenza outbreaks should be considered in other temperate zones.
评估2018 - 19年新南威尔士州夏季流感疫情与海外或国内旅行以及季节性流感疫苗接种状况的关联程度。
设计、背景：非匹配病例对照研究，基于从新南威尔士州法定传染病信息管理系统（NCIMS）向有手机号码的人群分发的在线调查。
病例定义为2018年12月1日至2019年3月21日期间发病且实验室确诊流感的人。被通知感染百日咳（确诊或疑似）的人被选为对照。
按发病前一周的旅行情况、与不适的海外旅行者接触情况以及季节性流感疫苗接种状况（作为主要暴露因素）来统计报告的流感感染情况。
2806名被邀请的报告流感患者中有648人（23%）提供了有效的调查回复，796名被邀请的报告百日咳患者中有257人（32%）提供了回复。受访者的人口统计学特征与源人群（7251例病例，2254名对照）相似。在2018 - 19年夏季的前两个月，发病前一周有过海外旅行或接触过患病海外旅行者的人报告流感的可能性更大（调整后的比值比[aOR]，6.99；95%置信区间，3.59 - 13.6），但在后两个月并非如此（aOR，1.63；95%置信区间，0.79 - 3.35）。流感疫苗接种状况与报告流感的可能性无关。
与旅行相关的因素是2018 - 19年新南威尔士州夏季流感疫情的早期驱动因素；尽管夏季后期条件不利，但本地传播维持了疫情爆发。我们的研究结果促使对新南威尔士州旅行前疫苗接种建议进行重新评估。其他温带地区应考虑旅行在非季节性流感爆发中的作用。
