Département de Médecine sociale et préventive, Université Laval, Québec, Canada.
Vaccine. 2010 Apr 26;28(19):3385-97. doi: 10.1016/j.vaccine.2010.02.079. Epub 2010 Mar 1.
In many countries, policymakers are being asked to make recommendations regarding the introduction of a 2-dose varicella vaccination program. The objective of this study was to examine the potential impact of 1-dose versus 2-dose varicella vaccination programs on varicella and zoster incidence, using Canada as an example. We developed a deterministic realistic age-structured model that fits 1- and 2-dose vaccine efficacy, varicella force of infection and zoster incidence. Assuming 90% coverage, the base case model (range: min; max) predicts that 1-dose vaccination will reduce varicella and zoster cases by 64% (14%; 96%) and 5% (-2%; 22%), respectively, over 80-years. Adding a second dose is predicted to reduce varicella and zoster by an additional 22% (0%; 82%) and 6% (0%; 14%), respectively. Most varicella cases prevented by the second dose are breakthrough infections. Although the incremental effectiveness of adding the second dose is highly sensitive to vaccine efficacy and mixing, predictions of the overall benefit of a 2-dose program is relatively robust to model assumptions. Adding a 2-dose program may help guarantee high population-level effectiveness against varicella. However, the incremental benefit of a second dose is highly dependant on the effectiveness of the first dose and its impact on zoster.
在许多国家，政策制定者被要求就引入两剂水痘疫苗接种计划提出建议。本研究旨在以加拿大为例，考察一剂与两剂水痘疫苗接种计划对水痘和带状疱疹发病率的潜在影响。我们开发了一种确定性现实年龄结构模型，该模型拟合了一剂和两剂疫苗的功效、水痘感染力和带状疱疹发病率。假设覆盖率为 90%，基础案例模型（范围：最小值；最大值）预测，一剂接种将使水痘和带状疱疹病例分别减少 64%（14%；96%）和 5%（-2%；22%），持续 80 年。接种第二剂预计将分别使水痘和带状疱疹再减少 22%（0%；82%）和 6%（0%；14%）。第二剂预防的大多数水痘病例是突破性感染。虽然增加第二剂的增效作用对疫苗效力和混合高度敏感，但两剂计划整体效益的预测对模型假设相对稳健。增加两剂计划可能有助于保证高水平的人群对水痘的有效性。然而，第二剂的增量效益高度依赖于第一剂的效果及其对带状疱疹的影响。
