Prevention of airborne smallpox transmission

描述（由申请人提供）：仅靠疫苗开发可能不足以保护美国免受天花生物恐怖袭击，特别是针对含有il - 4基因的工程病毒。即使有组织良好的疫苗接种规划，主要的脆弱性仍然存在，包括由于担心流行病和全国天花疫苗接种规划的发病率和死亡率而造成的大规模中断。因此，为响应RRGP-BTRR关于“暴露风险人群的新预防策略”的要求，我们建议研究紫外线（254 nm）杀菌照射（UVGI）作为预防大天花病毒在医院和其他公共建筑传播的策略的有效性。作为一项预防战略，空气卫生具有几个重要属性：它可以在疫情爆发前安全部署；它可以建立公众信心；它可以在确定疫情和开始疫苗接种运动之前的关键时期限制疫情的发展；通过减少其他空气传播感染的传播，即使天花从未发生，它也能对公共卫生产生好处。在这个项目中，我们将使用Acambis公司提供的低毒力牛痘病毒株作为大天花的模拟物。最初的实验将在一个小的气溶胶室中进行，以验证采样和分析方法，并确定UVGI诱导的牛痘指数衰减常数作为液滴核大小和相对湿度的函数。然后，我们将在医院房间大小的房间（4.5 m x 3 m x 2.9 m）中模拟“真实世界”的条件，以确定上层房间UVGI对消除痘病毒气溶胶的效用。雾化的病毒将收集在液体旋流取样器和级联撞击器中，并进行培养以确定感染性。上层房间的UVGI可以潜在地降低房间下层感染生物体的浓度，从而控制室内人员之间空气传播感染的传播，而不会使居住者暴露在大量紫外线下。这项工作将为决定是否建议在医院和公共建筑广泛实施上层房间UVGI作为抵御天花和其他生物工程空气传播感染的第一道防线提供可靠的科学依据。

DESCRIPTION (provided by applicant): Vaccine development alone may not be sufficient to protect the U.S. against bioterrorist attack with smallpox, especially against an engineered virus containing an IL4 gene. Major vulnerabilities remain, even with a well-organized vaccination program in place, including mass disruption caused by fear of an epidemic and the morbidity and mortality of a nationwide smallpox vaccination program. Therefore, in response to the RRGP-BTRR request for "new prevention strategies for those at risk of exposure," we propose to investigate the effectiveness of ultraviolet (254 nm) germicidal irradiation (UVGI) as a strategy for preventing dissemination of variola major virus in hospitals and other public buildings. As a prevention strategy air sanitation has several important attributes: it can be deployed safely before an outbreak; it can build public confidence; it can limit the growth of an outbreak during the critical period prior to identification of the outbreak and the start of a vaccination campaign; and it can have public health benefits even if an attack with smallpox never occurs by reducing spread of other airborne infections. In this project, we will use a low virulence vaccinia virus strain, provided by Acambis Corp., as a simulant for variola major. Initial experiments will be performed in a small aerosol chamber to validate sampling and analysis methods and to determine the UVGI induced exponential decay constants for vaccinia as a function of droplet nuclei size and relative humidity. Then, we will simulate "real world" conditions in a hospital room size chamber (4.5 m x 3 m x 2.9 m) to determine the utility of upper room UVGI for elimination of poxvirus aerosols. Aerosolized virus will be collected in a liquid swirling sampler and a cascade impactor and cultured to determine infectivity. Upper-room UVGI can potentially lower the concentration of infective organisms in the lower part of the room and thereby control the spread of airborne infections among room occupants, without exposing occupants to a significant amount of UV. This work will provide a sound scientific basis for decisions on whether to recommend wide spread implementation of upper room UVGI in hospitals and public buildings as a first line of defense against smallpox and other bioengineered airborne communicable infections.