World Health Organization, Avenue Appia, CH1211 Geneva 27, Switzerland.
J R Soc Interface. 2013 Jul 31;10(87):20130365. doi: 10.1098/rsif.2013.0365. Print 2013 Oct 6.
Approximately 100 million newborn children receive Bacille Calmette-Guérin (BCG) annually, because vaccination is consistently protective against childhood tuberculous meningitis and miliary TB. By contrast, BCG efficacy against pulmonary TB in children and adults is highly variable, ranging from 0% to 80%, though it tends to be higher in individuals who have no detectable prior exposure to mycobacterial infections, as judged by the absence of delayed-type hypersensitivity response (a negative tuberculin skin test, TST). The duration of protection against pulmonary TB is also variable, but lasts about 10 years on average. These observations raise the possibility that BCG revaccination, following primary vaccination in infancy, could be efficacious among TST-negative adolescents as they move into adulthood, the period of highest risk for pulmonary disease. To inform continuing debate about revaccination, this paper assesses the effectiveness and cost-effectiveness of revaccinating adolescents in a setting with intense transmission-Cape Town, South Africa. For a cost of revaccination in the range US$1-10 per person, and vaccine efficacy between 10% and 80% with protection for 10 years, the incremental cost per year of healthy life recovered (disability-adjusted life years, DALY) in the vaccinated population lies between US$116 and US$9237. The intervention is about twice as cost-effective when allowing for the extra benefits of preventing transmission, with costs per DALY recovered in the range US$52-$4540. At 80% efficacy, revaccination averted 17% of cases. Under the scenarios investigated, BCG revaccination is cost-effective against international benchmarks, though not highly effective. Cost-effectiveness ratios would be more favourable if we also allow for TB cases averted by preventing transmission to HIV-positive people, for the protection of HIV-negative people who later acquire HIV infection, for the possible non-specific benefits of BCG, for the fact that some adolescents would receive BCG for the first time, and for cost sharing when BCG is integrated into an adolescent immunization programme. These findings suggest, subject to further evaluation, that BCG revaccination could be cost-effective in some settings.
每年约有 1 亿新生儿接种卡介苗（BCG），因为该疫苗接种对儿童结核性脑膜炎和粟粒性结核具有持续的保护作用。相比之下，BCG 对儿童和成人肺结核的疗效差异很大，范围从 0%到 80%，尽管在那些根据迟发型超敏反应（结核菌素皮肤试验，TST 阴性）判断没有可检测到的先前分枝杆菌感染暴露的个体中，其疗效往往更高。针对肺结核的保护持续时间也各不相同，但平均约为 10 年。这些观察结果表明，在 TST 阴性青少年进入成年期（患肺部疾病风险最高的时期）后，对他们进行初次婴儿期接种后的 BCG 复种可能有效。为了为持续的复种辩论提供信息，本文评估了在南非开普敦这种强传播环境中对青少年进行复种的效果和成本效益。如果复种成本为每人 1-10 美元，疫苗效力为 10%至 80%，保护期为 10 年，则接种人群中每挽救一年健康生命的增量成本（残疾调整生命年，DALY）在 116 美元至 9237 美元之间。当考虑到预防传播的额外好处时，该干预措施的成本效益增加一倍，每挽救一个 DALY 的成本在 52 美元至 4540 美元之间。在 80%的疗效下，复种可避免 17%的病例。在所研究的方案下，BCG 复种符合国际基准的成本效益，但效果并不高。如果我们还考虑到预防传播对 HIV 阳性人群的结核病病例的影响、对后来感染 HIV 的 HIV 阴性人群的保护、BCG 可能的非特异性益处、一些青少年首次接种 BCG 的事实以及 BCG 整合到青少年免疫规划时的成本分担，那么成本效益比将更加有利。这些发现表明，在进一步评估的前提下，BCG 复种在某些情况下可能具有成本效益。
