Haahr S, Michelsen S W, Andersson M, Bjorn-Mortensen K, Soborg B, Wohlfahrt J, Melbye M, Koch A
Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.
Department of Clinical Medicine, University of Copenhagen, Denmark and.
Int J Epidemiol. 2016 Dec 1;45(6):2122-2130. doi: 10.1093/ije/dyw244.
The potential non-specific effects of BCG (Bacillus Calmette-Guérin) vaccination, with reported reduction of infectious disease morbidity among vaccinated children, in addition to the protective effect against tuberculosis (TB), are highly debated. In Greenland, BCG vaccination was introduced in 1955, but temporarily discontinued from 1991 to 1996 due to nationwide policy changes. Using the transient vaccination stop, we aimed to investigate possible non-specific effects of BCG vaccination by measuring nation-wide hospitalization rates due to infectious diseases other than TB among vaccinated and unvaccinated children.
A retrospective cohort study including all children born in Greenland aged 3 months to 3 years from 1989 to 2004. A personal identification number assigned at birth allowed for follow-up through national registers. Information on hospitalization due to infectious diseases was obtained from the Greenlandic inpatient register using ICD-8 and ICD-10 codes. Participants with notified TB were censored. Incidence rate ratios (IRR) were estimated using Poisson regression.
Overall, 19 363 children, hereof 66% BCG-vaccinated, were followed for 44 065 person-years and had 2069 hospitalizations due to infectious diseases. IRRs of hospitalization in BCG-vaccinated as compared with BCG-unvaccinated children were 1.07 [95% confidence interval (CI) 0.96-1.20] for infectious diseases overall, and specifically 1.10 (95% CI 0.98-1.24) for respiratory tract infections. Among BCG-vaccinated children aged 3 to 11 months, the IRR of hospitalization due to infectious diseases was 1.00 (95% CI 0.84-1.19) as compared with BCG-unvaccinated children.
Our results do not support the hypothesis that neonatal BCG vaccination reduces morbidity in children caused by infectious diseases other than TB.
卡介苗（BCG）接种除了对结核病（TB）有保护作用外，还报告称可降低接种儿童的传染病发病率，但其潜在的非特异性效应存在高度争议。在格陵兰岛，卡介苗接种于1955年引入，但由于全国性政策变化，于1991年至1996年暂时中断。利用这次短暂的接种中断，我们旨在通过测量接种和未接种儿童中除结核病以外的其他传染病导致的全国住院率，来研究卡介苗接种可能的非特异性效应。
一项回顾性队列研究，纳入了1989年至2004年在格陵兰岛出生的所有3个月至3岁的儿童。出生时分配的个人识别码允许通过国家登记册进行随访。使用国际疾病分类第8版（ICD - 8）和第10版（ICD - 10）编码，从格陵兰岛住院患者登记册中获取传染病住院信息。已报告结核病的参与者被排除。使用泊松回归估计发病率比（IRR）。
总体而言，19363名儿童接受了随访，随访时间为44065人年，其中66%接种了卡介苗，这些儿童因传染病住院2069次。接种卡介苗的儿童与未接种卡介苗的儿童相比，总体传染病住院的发病率比为1.07[95%置信区间（CI）0.96 - 1.20]，呼吸道感染的发病率比为1.10（95%CI 0.98 - 1.24）。在3至11个月大的接种卡介苗儿童中，与未接种卡介苗的儿童相比，因传染病住院的发病率比为1.00（95%CI 0.84 - 1.19）。
我们的结果不支持新生儿卡介苗接种可降低儿童除结核病以外的其他传染病发病率这一假设。
