Zar Heather J, Madhi Shabir A
Department of Paediatric Pulmonology and School of Child and Adolescent Health, Red Cross War Memorial Children's Hospital and University of Cape Town.
S Afr Med J. 2008 Jun;98(6):463-7.
Pneumonia is a major cause of childhood mortality and morbidity. Streptococcus pneumoniae is the most important bacterial pathogen causing pneumonia in children. The HIV epidemic has increased the burden and severity of childhood pneumococcal pneumonia and invasive disease fortyfold. Pneumococcal conjugate vaccine (PCV) is a highly effective intervention to reduce invasive pneumococcal disease and pneumonia. Studies evaluating a 9-valent PCV in South Africa and The Gambia reported a 72 - 77% reduction in vaccine-serotype-specific invasive disease in vaccinated children. As many of the pneumococcal serotypes associated with antibiotic resistance are included in PCV, vaccination has also been associated with a reduction in antimicrobial-resistant invasive disease. PCV may also reduce childhood mortality, especially in places with limited access to health care, as shown in Gambian study in which PCV reduced childhood mortality by 16%. In addition to the direct effects of PCV, there is a substantial reduction in disease burden through indirect protection of non-vaccinated populations. PCV is immunogenic in HIV-infected children and provides protection against invasive disease or pneumonia in a substantial number of children. Although the efficacy of PCV for prevention of invasive disease or pneumonia is lower in HIV-infected compared to -uninfected children, the overall burden of disease prevented is much greater in HIV-infected children because of the higher burden of pneumococcal disease in these children. Consequently, vaccine-preventable invasive disease is almost 60 times higher in HIV-infected compared to -uninfected children, while the reduction in pneumonia in HIV-infected children is 15 times greater. However, the long-term efficacy of PCV wanes in HIV-infected children who are not taking antiretroviral therapy, and booster doses are probably indicated. Although there is concern about the potential for replacement disease due to non-vaccine serotypes, a substantial and sustained reduction in invasive disease has occurred overall in populations with widespread childhood immunisation. Routine childhood immunisation is now the standard of care in most developed countries. However, PCV is much less accessible to children in developing countries due to cost and availability. Cost-effectiveness analysis indicates that use of PCV is potentially highly cost-effective, at tiered pricing, even in very low-income countries. Widespread availability and vaccination with PCV is urgently needed for all children under 2 years of age in South Africa. In addition, the use of PCV for all HIV-infected children under 9 years should be prioritised.
肺炎是儿童死亡和发病的主要原因。肺炎链球菌是导致儿童肺炎的最重要细菌病原体。艾滋病的流行使儿童肺炎球菌肺炎和侵袭性疾病的负担和严重程度增加了40倍。肺炎球菌结合疫苗（PCV）是减少侵袭性肺炎球菌疾病和肺炎的一种高效干预措施。在南非和冈比亚评估9价PCV的研究报告称，接种疫苗的儿童中疫苗血清型特异性侵袭性疾病减少了72%-77%。由于许多与抗生素耐药性相关的肺炎球菌血清型包含在PCV中，接种疫苗还与抗菌药物耐药性侵袭性疾病的减少有关。PCV还可能降低儿童死亡率，尤其是在医疗保健服务有限的地区，如冈比亚的一项研究表明PCV使儿童死亡率降低了16%。除了PCV的直接作用外，通过对未接种疫苗人群的间接保护，疾病负担也大幅减轻。PCV在感染HIV的儿童中具有免疫原性，并能为大量儿童提供针对侵袭性疾病或肺炎的保护。虽然与未感染儿童相比，PCV预防侵袭性疾病或肺炎的疗效在感染HIV的儿童中较低，但由于这些儿童肺炎球菌疾病负担较高，因此预防的疾病总体负担在感染HIV的儿童中要大得多。因此，与未感染儿童相比，感染HIV的儿童中可通过疫苗预防的侵袭性疾病几乎高60倍，而感染HIV的儿童中肺炎的减少幅度大15倍。然而，在未接受抗逆转录病毒治疗的感染HIV的儿童中，PCV的长期疗效会减弱，可能需要加强剂量。尽管人们担心非疫苗血清型可能导致替代疾病，但在广泛开展儿童免疫接种的人群中，侵袭性疾病总体上已大幅且持续减少。儿童常规免疫接种现在是大多数发达国家的标准治疗方法。然而，由于成本和可及性问题，发展中国家的儿童获得PCV的机会要少得多。成本效益分析表明，即使在非常低收入的国家，采用分级定价，使用PCV可能具有很高的成本效益。南非迫切需要为所有2岁以下儿童广泛提供PCV并进行接种。此外，应优先为所有9岁以下感染HIV的儿童使用PCV。
