Prevention of elderly pneumonia by BCG vaccination

对结核菌素的迟发型超敏反应是辅助性T细胞1介导的获得性免疫的重要标志。由于残疾老年人与抑郁结核菌素反应显示肺炎的风险增加，我们研究了卡介苗（BCG）管理对这些科目的肺炎的发展的影响。将88例结核菌素反应低下的老年残疾患者随机分为卡介苗接种组（n = 44）和未接种组（n = 44，NT组）。44例接受卡介苗接种的患者中有41例（93%）结核菌素阳转（CT组）。67例年龄匹配的结核菌素反应阳性患者（PT组）也入选。我们前瞻性地比较了这三组患者两年的肺炎发病率。在随访期间，NT组44例患者中有19例（42%）、CT组41例患者中有6例（15%）和PT组67例患者中有9例（13%）诊断为新型肺炎。根据考克斯回归模型，NT组与CT组相比发生肺炎的风险比为3.22（95%CI 1.03 - 9.96，P = 0.03）。此外，NT组因肺炎住院率显著高于CT组，相对危险度为7.14（95%CI 1.41 - 36.1，P = 0.03）。相反，CT组和PT组之间的肺炎风险无显著差异（P= 0.70）。这些发现表明，卡介苗接种可以重新激活免疫系统，降低失能老年人患肺炎的风险。

Delayed type hypersensitivity response to tuberculin is an important marker of T helper 1 mediated acquired immunity. Since the disabled elderly with depressed tuberculin responses show an increased risk of pneumonia, we examined the effect of Bacillus Calmette-Guerin (BCG) administration on the development of pneumonia in these subjects. Eighty-eight disabled older patients with depressed tuberculin responses were randomly assigned with BCG inoculation (n = 44) or without inoculation (n = 44, NT group). Forty-one (93%) of the 44 patients assigned with BCG inoculation showed positive tuberculin conversion (CT group). Sixty-seven age-matched patients with positive tuberculin responses (PT group) were also enrolled. We prospectively compared the rates of development of pneumonia for two years among these three groups. During follow-up, new pneumonia was diagnosed in 19 of the 44 patients (42%) in the NT group, 6 (15%) of the 41 patients in the CT group, and 9 (13%) of the 67 patients in the PT group. According to the Cox regression model, a hazard ratio of developing pneumonia in the NT group compared with the CT group was 3.22 (95% CI 1.03 -9.96, P = 0.03). Furthermore, the rate of hospitalization due to pneumonia was significantly higher in the NT group compared with the CT group with a relative risk of 7.14 (95% CI 1.41 -36.1, P = 0.03). Conversely, there was no significant difference in the risk of pneumonia between the CT group and the PT group (P= 0.70). These findings suggest that BCG inoculation could re-activate the immune system and reduce the risk of pneumonia in the disabled elderly.