Hansen John, Black Steven, Shinefield Henry, Cherian Thomas, Benson Jane, Fireman Bruce, Lewis Edwin, Ray Paula, Lee Janelle
Kaiser Permanente Vaccine Study Center, Oakland, CA 94612, USA.
Pediatr Infect Dis J. 2006 Sep;25(9):779-81. doi: 10.1097/01.inf.0000232706.35674.2f.
A World Health Organization (WHO) working group in 2001 developed a method for standardizing interpretation of chest radiographs in children for epidemiologic purposes. We reevaluated radiographs from the Kaiser Permanente Pneumococcal Efficacy trial using this method.
Seven-valent pneumococcal conjugate vaccine was evaluated in a randomized, controlled study including 37,868 infants. Effectiveness against pneumonia was previously evaluated using the original treating radiologist reading. There were 2841 sets of radiographs from this trial and all available radiographs were scanned and read blindly by 2 WHO crosstrained readers (A and B); discordance between the 2 primary readers was resolved through a consensus reading by an adjudicating panel of 2 radiologists.
Of the 2841 radiographs, 2446 were available for scanning and were reviewed using WHO-defined descriptive categories. Two hundred fifty of the 2446 radiographs were read as positive by both readers. An additional 129 were read as positive by reader A only and 142 by reader B only for a total of 521 radiographs that were read as positive by one or both of the reviewers. The concordance rate between the 2 reviewers was 250 of 521 (48%). Of the 271 discordant radiographs, 45 of 129 (34.9%) of reader A and 66 of 142 (46.5%) for reader B were finalized as positive by the adjudicating panel. Overall, 361 radiographs were finalized as positive (12.7%). With these 361 images as the standard, the sensitivity and specificity of reader A were 82% and 97%, respectively, and for reader B, 88% and 97%, respectively. Kappa between the 2 readers was 0.58. Of 25 control radiographs read as positive by both A and B, 80% were also read as positive by the panel and all 25 control negative radiographs were read as negative by the panel. Using original readings by point-of-care radiologists, efficacy against first episode of radiograph confirmed pneumonia was 17.7% (95% confidence interval [CI] = 4.8-28.9%) in intent-to-treat and 20.5% (95% CI = 4.4-34%) in per protocol. Using the WHO method, the efficacy against first episode of radiograph confirmed pneumonia adjusting for age, gender and year of vaccination of 25.5% (95% CI = 6.5-40.7%, P = 0.011) for intent-to-treat and 30.3% (95% CI = 10.7-45.7%, P = 0.0043) for per protocol.
Using WHO criteria for reading of radiographs increased point estimates of vaccine efficacy presumably as a result of improved specificity.
2001年，世界卫生组织（WHO）一个工作组制定了一种方法，用于标准化儿童胸部X光片的解读，以用于流行病学目的。我们使用这种方法重新评估了凯撒医疗集团肺炎球菌疫苗效力试验中的X光片。
在一项随机对照研究中对七价肺炎球菌结合疫苗进行了评估，该研究纳入了37868名婴儿。先前使用最初的主治放射科医生的读片结果评估了疫苗对肺炎的效力。该试验共有2841套X光片，所有可用的X光片都由两名经过WHO交叉培训的阅片者（A和B）进行扫描并盲法阅片；两位主要阅片者之间的分歧通过由两名放射科医生组成的裁决小组进行共识阅片来解决。
在2841张X光片中，有2446张可供扫描，并使用WHO定义的描述性类别进行了复查。2446张X光片中，有250张被两位阅片者都判读为阳性。另有129张仅被阅片者A判读为阳性，142张仅被阅片者B判读为阳性，因此共有521张X光片被一位或两位阅片者判读为阳性。两位阅片者之间的一致率为521张中的250张（48%）。在271张有分歧的X光片中，阅片者A的129张中有45张（34.9%）以及阅片者B的142张中有66张（46.5%）被裁决小组最终判定为阳性。总体而言，361张X光片最终被判定为阳性（12.7%）。以这361张影像作为标准，阅片者A的敏感度和特异度分别为82%和97%，阅片者B的敏感度和特异度分别为88%和97%。两位阅片者之间的kappa值为0.58。在被A和B都判读为阳性的25张对照X光片中，80%也被裁决小组判读为阳性，所有25张对照阴性X光片都被裁决小组判读为阴性。根据即时护理放射科医生的原始读片结果，在意向性治疗中，疫苗对X光片确诊的首次肺炎发作的效力为17.7%（95%置信区间[CI]=4.8 - 28.9%），在符合方案分析中为20.5%（95%CI = 4.4 - 34%）。使用WHO方法，在意向性治疗中，针对X光片确诊的首次肺炎发作，在调整年龄、性别和疫苗接种年份后，效力为25.5%（95%CI = 6.5 - 40.7%，P = 0.011），在符合方案分析中为30.3%（95%CI = 10.7 - 45.7%，P = 0.0043）。
使用WHO的X光片判读标准提高了疫苗效力的点估计值，这可能是由于特异度提高所致。
