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标题：Effectiveness of Border Screening for Detecting Influenza in Arriving Airline Travelers
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作者：Patricia C. Priest ; Lance C. Jennings ; Alasdair R. Duncan 等
期刊名称：American journal of public health
印刷版ISSN：0090-0036
出版年度：2015
卷号：105
期号：Suppl 4
页码：S607-S613
DOI：10.2105/AJPH.2012.300761r
语种：English
出版社：American Public Health Association
摘要：Objectives. We measured symptom and influenza prevalence, and the effectiveness of symptom and temperature screening for identifying influenza, in arriving international airline travelers. Methods. This cross-sectional study collected data from travelers to Christchurch International Airport, New Zealand, in winter 2008, via a health questionnaire, temperature testing, and respiratory sampling. Results. Forms were returned by 15 976 (68%) travelers. Of these, 17% reported at least 1 influenza symptom, with runny or blocked nose (10%) and cough (8%) most common. Respiratory specimens were obtained from 3769 travelers. Estimated prevalence of influenza was 1.1% (4% among symptomatic, 0.2% among asymptomatic). The sensitivity of screening criteria ranged from 84% for “any symptom” to 3% for a fever of 37.8 °C or greater. The positive predictive value was low for all criteria. Conclusions. Border screening using self-reported symptoms and temperature testing has limitations for preventing pandemic influenza from entering a country. Using “any symptom” or cough would lead to many uninfected people being investigated, yet some infected people would remain undetected. If more specific criteria such as fever were used, most infected people would enter the country despite screening. Border screening to prevent or delay entry of a pandemic influenza virus to a country is intuitively appealing. Identifying infected travelers and turning them back before they commenced travel, or isolating or quarantining them on arrival, would reduce the probability that they would infect people in the destination country. The evidence base for decisions on border screening has consisted of reviews of previous influenza pandemic experiences and severe acute respiratory syndrome (SARS), and the results of modeling studies. Although entry and exit screening and quarantine measures were successful in delaying entry of the 1918 pandemic virus to some island countries, border screening for SARS was not found to be cost-effective. 1 During the pandemic of influenza A (H1N1) 2009, some countries implemented entry screening, although it is unclear how effective it was in delaying entry of the virus 2 ; for example, only 15 of 116 travel-associated cases in Singapore were detected at the airport. 3 The results of modeling studies of the effect of border management to prevent the entry of influenza indicate that a very high proportion of infected travelers (> 99%) would need to be prevented from entering the community to have an important impact on the epidemic in a country, 4–6 and even then entry screening is unlikely to be effective in preventing importation. 7,8 However, all modeling studies must make assumptions about some variables in the models: for example, the proportion of airline travelers who are infected with influenza, symptomatically and asymptomatically. The World Health Organization’s most recent guidance on pandemic response suggests that countries could consider implementing exit screening (the first few affected countries) or entry screening (as yet unaffected countries) for a limited period at the beginning of a pandemic. 9 However, identifying infected arriving travelers is not straightforward. A simple, cheap, quick, and highly accurate test for influenza that could be used on all travelers is not currently available. 10 Therefore, signs and symptoms of influenza must be used to screen travelers to identify those most likely to be infected, for further testing. Influenza screening using symptom questionnaires has inherent limitations to its sensitivity and, hence, effectiveness. Travelers who do not identify themselves as symptomatic will not be detected. These will include those who choose not to disclose symptoms or who use medication to suppress them, and those with no or very mild symptoms on arrival in a country. The latter group includes some who will never develop noticeable symptoms 11 and those incubating infection acquired before or during the flight. 12,13 Conversely, symptom screening will identify a number of travelers with symptoms not caused by influenza; this could overwhelm testing and quarantine or isolation resources. The aim of this study was to estimate previously unmeasured characteristics of influenza in international travelers, including the prevalence of symptoms and influenza infection (symptomatic and asymptomatic), during a winter influenza season. By assessing the effectiveness of a health questionnaire and temperature testing for entry screening for seasonal influenza, the study aimed to draw conclusions about their likely effectiveness for pandemic influenza.