Methods and challenges for the health impact assessment of vaccination programs in Latin America

ABSTRACT OBJECTIVE To describe methods and challenges faced in the health impact assessment of vaccination programs, focusing on the pneumococcal conjugate and rotavirus vaccines in Latin America and the Caribbean. METHODS For this narrative review, we searched for the terms "rotavirus", "pneumococcal", "conjugate vaccine", "vaccination", "program", and "impact" in the databases Medline and LILACS. The search was extended to the grey literature in Google Scholar. No limits were defined for publication year. Original articles on the health impact assessment of pneumococcal and rotavirus vaccination programs in Latin America and the Caribbean in English, Spanish or Portuguese were included. RESULTS We identified 207 articles. After removing duplicates and assessing eligibility, we reviewed 33 studies, 25 focusing on rotavirus and eight on pneumococcal vaccination programs. The most frequent studies were ecological, with time series analysis or comparing pre- and post-vaccination periods. The main data sources were: health information systems; population-, sentinel- or laboratory-based surveillance systems; statistics reports; and medical records from one or few health care services. Few studies used primary data. Hospitalization and death were the main outcomes assessed. CONCLUSIONS Over the last years, a significant number of health impact assessments of pneumococcal and rotavirus vaccination programs have been conducted in Latin America and the Caribbean. These studies were carried out few years after the programs were implemented, meet the basic methodological requirements and suggest positive health impact. Future assessments should consider methodological issues and challenges arisen in these first studies conducted in the region.

摘要 目的 描述疫苗接种项目健康影响评估所采用的方法及面临的挑战，重点聚焦拉丁美洲与加勒比地区的肺炎球菌结合疫苗（pneumococcal conjugate vaccine）和轮状病毒疫苗（rotavirus vaccine）。方法 本研究为叙述性综述（narrative review），在Medline与LILACS数据库中检索“轮状病毒（rotavirus）”“肺炎球菌（pneumococcal）”“结合疫苗（conjugate vaccine）”“疫苗接种（vaccination）”“项目（program）”及“影响（impact）”相关术语，并将检索范围扩展至Google Scholar中的灰色文献（grey literature），未限定发表年份。纳入以英语、西班牙语或葡萄牙语发表的、针对拉丁美洲与加勒比地区肺炎球菌及轮状病毒疫苗接种项目健康影响评估的原创性研究。结果 共检索到207篇文献，去除重复文献并完成资格评估后，最终纳入33项研究：其中25项聚焦轮状病毒疫苗接种项目，8项聚焦肺炎球菌疫苗接种项目。此类研究多为生态学研究（ecological study），采用时间序列分析（time series analysis）或对比疫苗接种前后的时段。主要数据来源包括：健康信息系统、基于人群、哨点或实验室的监测系统、统计报告，以及单个或少数医疗服务机构的医疗记录；仅有少数研究采用原始数据。评估的主要结局指标为住院与死亡情况。结论 近年来，拉丁美洲与加勒比地区已开展大量针对肺炎球菌及轮状病毒疫苗接种项目的健康影响评估研究。此类研究多在项目实施数年后开展，满足基本方法学要求，且提示疫苗接种具有积极健康影响。未来的评估研究应考虑该地区首批此类研究所面临的方法学问题与挑战。