Nuño M, Reichert T A, Chowell G, Gumel A B
Department of Biostatistics, School of Public Health, University of California, Los Angeles, CA 90095-1772, USA.
Proc Natl Acad Sci U S A. 2008 Jul 29;105(30):10625-30. doi: 10.1073/pnas.0712014105. Epub 2008 Jul 22.
It is widely believed that protecting health care facilities against outbreaks of pandemic influenza requires pharmaceutical resources such as antivirals and vaccines. However, early in a pandemic, vaccines will not likely be available and antivirals will probably be of limited supply. The containment of pandemic influenza within acute-care hospitals anywhere is problematic because of open connections with communities. However, other health care institutions, especially those providing care for the disabled, can potentially control community access. We modeled a residential care facility by using a stochastic compartmental model to address the question of whether conditions exist under which nonpharmaceutical interventions (NPIs) alone might prevent the introduction of a pandemic virus. The model projected that with currently recommended staff-visitor interactions and social distancing practices, virus introductions are inevitable in all pandemics, accompanied by rapid internal propagation. The model identified staff reentry as the critical pathway of contagion, and provided estimates of the reduction in risk required to minimize the probability of a virus introduction. By using information on latency for historical and candidate pandemic viruses, we developed NPIs that simulated notions of protective isolation for staff away from the facility that reduced the probability of bringing the pandemic infection back to the facility to levels providing protection over a large range of projected pandemic severities. The proposed form of protective isolation was evaluated for social plausibility by collaborators who operate residential facilities. It appears unavoidable that NPI combinations effective against pandemics more severe than mild imply social disruption that increases with severity.
人们普遍认为，保护医疗保健设施免受大流行性流感爆发的影响需要抗病毒药物和疫苗等药物资源。然而，在大流行初期，疫苗可能无法获得，抗病毒药物的供应可能也有限。由于与社区的开放联系，在任何地方的急症医院内控制大流行性流感都存在问题。然而，其他医疗保健机构，特别是那些为残疾人提供护理的机构，有可能控制社区人员的进入。我们使用随机分区模型对一家寄宿护理机构进行了建模，以解决仅通过非药物干预（NPIs）是否可能预防大流行病毒传入的问题。该模型预测，按照目前推荐的工作人员与访客互动以及社交距离措施，在所有大流行中病毒传入都是不可避免的，并且会伴随病毒在机构内的快速传播。该模型确定工作人员再次进入机构是传播的关键途径，并提供了为将病毒传入的概率降至最低所需降低的风险估计值。通过利用关于历史和候选大流行病毒潜伏期的信息，我们制定了非药物干预措施，模拟了对离开机构的工作人员进行保护性隔离的概念，从而将大流行感染带回机构的概率降低到在一系列预计的大流行严重程度下都能提供保护的水平。经营寄宿护理机构的合作者对所提议的保护性隔离形式进行了社会合理性评估。对于比轻度大流行更严重的大流行，有效的非药物干预措施组合似乎不可避免地意味着会随着严重程度的增加而导致社会混乱。
