Mulholland K
Division of Vaccines and Biologicals, World Health Organization, Geneva, Switzerland.
Clin Infect Dis. 2000 Jun;30 Suppl 3:S206-9. doi: 10.1086/313863.
Bacterial pneumonia in children is usually caused by one of the two leading pathogens, Streptococcus pneumoniae (pneumococcus) and Haemophilus influenzae, either type b (Hib) or nonencapsulated types. Hib conjugate vaccines suitable for use in infants have been available for about a decade, and experience with a trial of one of these vaccines in Africa showed that the vaccines can prevent Hib pneumonia, as well as other manifestations of Hib disease. It also showed that vaccine trials can provide useful estimates of the role of Hib in childhood pneumonia. Trials of pneumococcal conjugate vaccines that are currently under way have been designed to estimate disease burden and efficacy. A major risk of vaccine trials that use bacteriologic end points is that the vaccine may affect the diagnostic test itself, creating a misleading impression of efficacy. Trials of future tuberculosis vaccines are discussed in light of these experiences. It is important that the trials are designed to measure the effect on all clinical disease, as well as strict microbiological end points. The existence of bacille Calmette-Guérin (BCG) complicates future trials, and such trials should take into account possible nonspecific effects of BCG in addition to its effect on tuberculosis.
儿童细菌性肺炎通常由两种主要病原体之一引起，即肺炎链球菌（肺炎球菌）和b型流感嗜血杆菌（Hib）或非包膜型流感嗜血杆菌。适用于婴儿的Hib结合疫苗已经问世约十年，在非洲对其中一种疫苗进行的试验表明，这些疫苗可以预防Hib肺炎以及Hib疾病的其他表现。该试验还表明，疫苗试验可以对Hib在儿童肺炎中的作用提供有用的评估。目前正在进行的肺炎球菌结合疫苗试验旨在评估疾病负担和效力。使用细菌学终点的疫苗试验的一个主要风险是，疫苗可能会影响诊断测试本身，从而产生关于效力的误导性印象。鉴于这些经验，对未来结核病疫苗试验进行了讨论。重要的是，试验设计应旨在衡量对所有临床疾病的影响以及严格的微生物学终点。卡介苗（BCG）的存在使未来的试验变得复杂，此类试验除了要考虑BCG对结核病的影响外，还应考虑其可能的非特异性作用。
