Hanna Jeffrey N, Smith Greg A, McCulloch Bradley G, Taylor Carmel T, Pyke Alyssa T, Brookes Dianne L
Tropical Public Health Unit Network, Queensland Health, Cairns.
Aust N Z J Public Health. 2005 Feb;29(1):44-7. doi: 10.1111/j.1467-842x.2005.tb00747.x.
Japanese encephalitis (JE) emerged for the first time in the Torres Strait, north Australia, in 1995. The inactivated mouse-brain derived JE vaccine was offered to all residents of the outer Torres Strait Islands prior to the 1996 wet season. This study was undertaken to determine the appropriateness of the recommended three-year interval between booster doses of the vaccine.
JE neutralising antibody was measured in residents of Badu Island for whom 30-36 months had passed since either a previous booster or the completion of the primary immunisation series.
Only 70 (32%) of 219 eligible individuals had protective antibodies; 50 (37%) of the adults were immune, compared with 20 (24%) of the children (odds ratio (OR) 1.93; 95% confidence interval (CI) 1.01-3.74).
This low level of immunity suggests that there is little in the way of natural boosting from either JE or other closely related viruses. Given the apparent low level of risk of exposure to the JE virus in the Torres Strait, and the logistical complexities involved in delivering the booster doses, the current recommendation of a three-year interval is not inappropriate.
It would be advantageous to have a JE vaccine that is not only safer but also more immunogenic, so that it might be possible to further increase the booster dose interval.
1995年，日本脑炎（乙脑）首次在澳大利亚北部的托雷斯海峡出现。在1996年雨季来临之前，为托雷斯海峡外岛的所有居民提供了源自鼠脑的灭活乙脑疫苗。本研究旨在确定推荐的疫苗加强剂量之间三年间隔的合理性。
对巴杜岛居民进行乙脑中和抗体检测，这些居民自上次加强免疫或完成基础免疫系列后已过去30 - 36个月。
219名符合条件的个体中，只有70人（32%）具有保护性抗体；50名成年人（37%）有免疫力，而儿童中有20人（24%）有免疫力（优势比（OR）1.93；95%置信区间（CI）1.01 - 3.74）。
这种低水平的免疫力表明，无论是乙脑还是其他密切相关病毒，自然增强免疫力的作用都很小。鉴于托雷斯海峡接触乙脑病毒的风险明显较低，以及提供加强剂量所涉及的后勤复杂性，目前推荐的三年间隔并非不合适。
拥有一种不仅更安全而且免疫原性更强的乙脑疫苗将是有利的，这样有可能进一步延长加强剂量的间隔时间。
