The WHO Review of the Possible Nonspecific Effects of Diphtheria-Tetanus-Pertussis Vaccine
The WHO Review of the Possible Nonspecific Effects of Diphtheria-Tetanus-Pertussis Vaccine
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DOI：
10.1097/inf.0000000000001269
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发表时间：
2016-11-01
影响因子：
3.6
通讯作者：
Benn, Christine S.
中科院分区：
文献类型：
--
作者：
Aaby, Peter;Ravn, Henrik;Benn, Christine S.
背景：世界卫生组织最近审查了白喉-破伤风-百日咳（DTP）疫苗可能产生的非特异性效应。尽管大多数研究表明有害影响，但结果被认为是不一致的。我们研究了结果的不一致是否反映了DTP的效果差异或在不同的study.Methods中使用的方法的差异：如果儿童仍然未接种疫苗，因为他们是体弱的，或者如果儿童（包括死亡的）没有接种疫苗的状态信息被归类为“未接种疫苗”，死亡率变得不自然的高之间的“未接种疫苗”的控制。为了衡量这种偏差，我们定义的“偏差指数”之间的未接种疫苗和接种疫苗的儿童死亡率比（MRR）。结果：5项研究有虚弱或定义不清的对照组和生存偏倚，偏差指数为2.0-8.0，在这些研究中，DTP与MRR为0.39（0.18-0.83）。8项研究通过接种卡确定“未接种”，偏倚指数为0.5-1.7;在这些研究中，DTP与MRR为2.00（1.50-2.67）相关。结论：观察到的结果不一致是由于研究之间的方法学差异。偏倚似乎不能解释为什么DTP与较高的死亡率相关。
Background: World Health Organization recently reviewed the possible non-specific effects of diphtheria-tetanus-pertussis (DTP) vaccine. The results were considered inconsistent though most studies suggested deleterious effects. We examined whether inconsistencies in results reflected differences in effect of DTP or differences in the methodology used in different studies.Methods: If children remain unvaccinated because they are frail or if children (including dead ones) with no information on vaccination status are classified as "unvaccinated," the mortality rate becomes unnaturally high among "unvaccinated" controls. To measure this bias, we defined the "bias index" as the mortality rate ratio (MRR) between unvaccinated and vaccinated children.Results: Five studies had frail or poorly defined control groups and survival bias, the bias index being 2.0-8.0; in these studies DTP was associated with an MRR of 0.39 (0.18-0.83). Eight studies determined "unvaccinated" by vaccination card and the bias index was 0.5-1.7; in these studies DTP was associated with an MRR of 2.00 (1.50-2.67).Conclusion: The observed inconsistencies in results were because of methodologic differences between studies. Bias does not seem to explain why DTP is associated with higher mortality.