Pneumococcal Research Group, Murdoch Children's Research Institute, Melbourne, Australia.
Department of Paediatrics, The University of Melbourne, Melbourne, Australia.
BMC Public Health. 2019 Mar 21;19(1):333. doi: 10.1186/s12889-019-6639-y.
Streptococcus pneumoniae causes substantial morbidity and mortality among children. The introduction of pneumococcal conjugate vaccines (PCV) has the potential to dramatically reduce disease burden. As with any vaccine, it is important to evaluate PCV impact, to help guide decision-making and resource-allocation. Measuring PCV impact can be complex, particularly to measure impact on one of the most common and significant diseases caused by the pneumococcus, namely pneumonia. Here we outline the protocol developed to evaluate the impact of 13-valent PCV (PCV13) on childhood pneumonia in Mongolia, and a number of lessons learned in implementing the evaluation that may be helpful to other countries seeking to undertake pneumonia surveillance.
From 2016 PCV13 was introduced in a phased manner into the routine immunisation programme with some catch-up by the Government of Mongolia. We designed an evaluation to measure vaccine impact in children aged 2-59 months with hospitalised radiological pneumonia as a primary outcome, with secondary objectives to measure impact on clinically-defined pneumonia, nasopharyngeal carriage of S. pneumoniae among pneumonia patients and in the community, and severe respiratory infection associated with RSV and/or influenza. We enhanced an existing hospital-based pneumonia surveillance system by incorporating additional study components (nasopharyngeal swabbing using standard methods, C-reactive protein, risk factor assessment) and strengthening clinical practices, such as radiology as well as monitoring and training. We conducted cross-sectional community carriage surveys to provide data on impact on carriage among healthy children.
Establishing a robust surveillance system is an important component of monitoring the impact of PCV within a country. The enhanced surveillance system in Mongolia will facilitate assessment of PCV13 impact on pneumonia, with radiological confirmed disease as the primary outcome. Key lessons arising from this evaluation have included the importance of establishing a core group of in-country staff to be responsible for surveillance activities and to work closely with this team; to be aware of external factors that could potentially influence disease burden estimates; to be flexible in data collection processes to respond to changing circumstances and lastly to ensure a consistent application of the pneumonia surveillance case definition throughout the study period.
肺炎链球菌可导致儿童发病和死亡。接种肺炎球菌结合疫苗（PCV）有可能显著降低疾病负担。与任何疫苗一样，评估 PCV 的影响非常重要，有助于指导决策和资源分配。衡量 PCV 的影响可能很复杂，尤其是要衡量其对肺炎球菌引起的最常见和最严重疾病之一（即肺炎）的影响。在这里，我们概述了为评估 13 价肺炎球菌结合疫苗（PCV13）对蒙古儿童肺炎的影响而制定的方案，并总结了实施评估过程中获得的一些经验教训，这些经验教训可能对其他寻求开展肺炎监测的国家有所帮助。
从 2016 年开始，PCV13 分阶段纳入常规免疫规划，蒙古政府还进行了一些补种。我们设计了一项评估，以衡量疫苗对 2-59 月龄因放射影像学确诊肺炎住院的儿童的影响，次要目标是衡量对临床定义的肺炎、肺炎患者和社区中肺炎链球菌鼻咽携带率以及与呼吸道合胞病毒和/或流感相关的严重呼吸道感染的影响。我们通过纳入额外的研究内容（使用标准方法进行鼻咽拭子采样、C 反应蛋白、危险因素评估）和加强临床实践（如放射学以及监测和培训），增强了现有的基于医院的肺炎监测系统。我们还开展了横断面社区携带率调查，以提供健康儿童携带率方面的数据。
建立一个强大的监测系统是监测国家内 PCV 影响的重要组成部分。蒙古强化的监测系统将有助于评估 PCV13 对肺炎的影响，以放射学确诊的疾病为主要结局。本次评估中得出的重要经验教训包括：建立一个由国内工作人员组成的核心小组负责监测活动并与该小组密切合作的重要性；意识到可能影响疾病负担估计的外部因素；灵活处理数据收集流程，以应对不断变化的情况；最后，确保在整个研究期间一致应用肺炎监测病例定义。
