PATH, Seattle, Washington, United States of America.
PATH Hanoi Towers, Hanoi, Vietnam.
PLoS Negl Trop Dis. 2024 Sep 3;18(9):e0012390. doi: 10.1371/journal.pntd.0012390. eCollection 2024 Sep.
Japanese encephalitis (JE) virus is the leading cause of vaccine-preventable encephalitis and a significant cause of disability in Asia and the western Pacific. Many countries have introduced JE vaccination programs, including several low resource countries following WHO's prioritization of JE vaccination in 2006. We sought to characterize the public health impact of JE vaccination programs.
METHODOLOGY/PRINCIPAL FINDINGS: JE case data and vaccination coverage rates, were requested from country health officials in 23 JE endemic countries and Chinese Taipei. Additional data were extracted from meeting presentations and published literature. JE incidence was compared before and after vaccination using a minimum three year period pre and post program introduction or expansion. Data suitable for analysis were available for 13 JE-endemic countries and Chinese Taipei, for either all age groups or for children aged under 15 years only. Five countries and Chinese Taipei introduced vaccine prior to 2006 and the all-age JE incidence was reduced by 73-100% in about 5-20 years following introduction. Six countries have introduced JE vaccine since 2006, and JE incidence in children aged younger than 15 years has been reduced by 14-79% as of 2015-2021. JE-specific data were unavailable before introduction in Thailand and Vietnam, but vaccination programs reduced acute encephalitis incidence by 80% and 74%, respectively. Even in the programs with greatest impact, it took several years to achieve their results.
CONCLUSIONS/SIGNIFICANCE: JE vaccination has greatly reduced JE in 13 JE-endemic countries and Chinese Taipei. Highest impact has been observed in countries that introduced prior to 2006, but it often took roughly two decades and substantial resources to achieve that level of success. For greatest possible impact, more recently introducing countries and funding agencies should commit to continuous improvements in delivery systems to sustain coverage after initial vaccine introduction.
日本脑炎（JE）病毒是可通过疫苗预防的脑炎的主要原因，也是亚洲和西太平洋地区残疾的重要原因。许多国家已经推出了 JE 疫苗接种计划，包括一些资源较少的国家，这些国家遵循了世卫组织 2006 年对 JE 疫苗接种的优先排序。我们旨在描述 JE 疫苗接种计划对公共卫生的影响。
方法/主要发现：我们向 23 个 JE 流行国家和中国台湾的国家卫生官员请求 JE 病例数据和疫苗接种覆盖率数据。从会议报告和已发表的文献中提取了其他数据。使用接种前至少三年的时间段，比较了接种前后 JE 的发病率。可以分析的数据适用于 13 个 JE 流行国家和中国台湾，适用于所有年龄组或仅适用于 15 岁以下儿童。五个国家和中国台湾在 2006 年之前引入了疫苗，并且在引入疫苗后大约 5-20 年内，全年龄段 JE 的发病率降低了 73-100%。自 2006 年以来，有六个国家引入了 JE 疫苗，截至 2015-2021 年，15 岁以下儿童的 JE 发病率降低了 14-79%。泰国和越南在引入疫苗之前没有 JE 特定数据，但疫苗接种计划将急性脑炎的发病率分别降低了 80%和 74%。即使在影响最大的计划中，也需要几年时间才能取得成果。
结论/意义：JE 疫苗接种大大降低了 13 个 JE 流行国家和中国台湾的 JE 发病率。在那些 2006 年之前引入疫苗的国家，影响最大，但要达到这种成功水平，往往需要大约二十年和大量资源。为了取得最大的影响，最近引入国家和资助机构应承诺不断改进交付系统，以维持初始疫苗接种后的覆盖范围。
