Department of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand.
PLoS One. 2011 Jan 5;6(1):e14490. doi: 10.1371/journal.pone.0014490.
Infrared thermal image scanners (ITIS) appear an attractive option for the mass screening of travellers for influenza, but there are no published data on their performance in airports.
ITIS was used to measure cutaneous temperature in 1275 airline travellers who had agreed to tympanic temperature measurement and respiratory sampling. The prediction by ITIS of tympanic temperature (37.8°C and 37.5°C) and of influenza infection was assessed using Receiver Operating Characteristic (ROC) curves and estimated sensitivity, specificity and positive predictive value (PPV).
Using front of face ITIS for prediction of tympanic temperature ≥37.8°C, the area under the ROC curve was 0.86 (95%CI 0.75-0.97) and setting sensitivity at 86% gave specificity of 71%. The PPV in this population of travellers, of whom 0.5% were febrile using this definition, was 1.5%. We identified influenza virus infection in 30 travellers (3 Type A and 27 Type B). For ITIS prediction of influenza infection the area under the ROC curve was 0.66 (0.56-0.75), a sensitivity of 87% gave specificity of 39%, and PPV of 2.8%. None of the 30 influenza-positive travellers had tympanic temperature ≥37.8°C at screening (95%CI 0% to 12%); three had no influenza symptoms.
ITIS performed moderately well in detecting fever but in this study, during a seasonal epidemic of predominantly influenza type B, the proportion of influenza-infected travellers who were febrile was low and ITIS were not much better than chance at identifying travellers likely to be influenza-infected. Although febrile illness is more common in influenza A infections than influenza B infections, many influenza A infections are afebrile. Our findings therefore suggest that ITIS is unlikely to be effective for entry screening of travellers to detect influenza infection with the intention of preventing entry of the virus into a country.
红外热像扫描仪（ITIS）似乎是流感旅客大规模筛查的一个有吸引力的选择，但目前尚无关于其在机场表现的发表数据。
使用 ITIS 测量了 1275 名航空公司旅客的皮肤温度，这些旅客同意进行鼓膜温度测量和呼吸道采样。使用 ROC 曲线和估计的敏感性、特异性和阳性预测值（PPV）评估 ITIS 对鼓膜温度（37.8°C 和 37.5°C）和流感感染的预测。
使用面部 ITIS 预测鼓膜温度≥37.8°C，ROC 曲线下面积为 0.86（95%CI 0.75-0.97），将敏感性设定为 86%，特异性为 71%。在这群旅行者中，使用该定义有 0.5%的人发热，其阳性预测值为 1.5%。我们在 30 名旅行者中发现了流感病毒感染（3 型 A 和 27 型 B）。对于 ITIS 预测流感感染，ROC 曲线下面积为 0.66（0.56-0.75），敏感性为 87%，特异性为 39%，阳性预测值为 2.8%。在筛查时，没有 30 名流感阳性旅行者的鼓膜温度≥37.8°C（95%CI 0%至 12%）；其中 3 人没有流感症状。
ITIS 在检测发热方面表现良好，但在本研究中，在以乙型流感为主的季节性流行期间，流感感染旅行者中发热的比例较低，ITIS 在识别可能感染流感的旅行者方面并不比随机更好。虽然发热性疾病在甲型流感感染中比乙型流感感染更为常见，但许多甲型流感感染并不发热。因此，我们的研究结果表明，ITIS 不太可能有效地用于旅行者入境筛查，以检测流感感染，从而防止病毒进入一个国家。
