Jacobson Sheldon H, Sewell Edward C, Proano Ruben A
Department of Computer Science, Simulation and Optimization Laboratory, University of Illinois, Urbana, IL 61801, USA.
Health Care Manag Sci. 2006 Nov;9(4):371-89. doi: 10.1007/s10729-006-0001-5.
In 2002, several factors resulted in pediatric vaccine manufacturers not being able to produce a sufficient number of vaccines to vaccinate all the children in the United States according to the Recommended Childhood Immunization Schedule. The resulting vaccine supply shortage resulted in thousands of children not being fully immunized according to this schedule, and hence, created an unnecessary risk for epidemic outbreaks of several childhood diseases. The Centers for Disease Control and Prevention responded to this crisis by using pediatric vaccine stockpiles to mitigate the impact of future shortages. This paper presents a stochastic model that captures the vaccine supply during production interruptions. This model is used to assess the impact of pediatric vaccine stockpile levels on vaccination coverage rates, by considering the probability that all children can be immunized according to the Recommended Childhood Immunization Schedule over a given time period and the expected minimum vaccine supply. The model is also used to assess the proposed pediatric vaccine stockpile levels recommended by the United States Department of Health and Human Services. The results of this analysis suggest that the proposed vaccine stockpile levels are adequate to meet future vaccine production interruptions, provided that such production interruptions do not last more than six months (which is not surprising, given that is the time period for which they were designed). However, given that recent vaccine production interruptions have lasted (on average) for over one year, the proposed vaccine stockpile levels are insufficient to meet the nation's pediatric immunization needs during such time periods, which in turn could lead to localized and/or widespread disease outbreaks. Moreover, a moderate investment in higher vaccine stockpile levels would lead to a significantly reduced risk of such events.
2002年，多种因素导致儿科疫苗生产商无法按照《儿童免疫接种推荐时间表》生产出足够数量的疫苗来为美国所有儿童接种。由此产生的疫苗供应短缺致使数千名儿童未能按照该时间表完全接种疫苗，进而为几种儿童疾病的流行爆发带来了不必要的风险。疾病控制与预防中心通过动用儿科疫苗储备来缓解未来短缺的影响，应对了这一危机。本文提出了一个随机模型，该模型能够捕捉生产中断期间的疫苗供应情况。通过考虑在给定时间段内所有儿童都能按照《儿童免疫接种推荐时间表》接种疫苗的概率以及预期的最低疫苗供应量，此模型用于评估儿科疫苗储备水平对疫苗接种覆盖率的影响。该模型还用于评估美国卫生与公众服务部建议的儿科疫苗储备水平。分析结果表明，建议的疫苗储备水平足以应对未来的疫苗生产中断情况，前提是此类生产中断持续时间不超过六个月（鉴于这是储备设计所针对的时间段，这并不奇怪）。然而，鉴于近期疫苗生产中断平均持续时间超过一年，建议的疫苗储备水平不足以满足该时间段内国家的儿科免疫需求，这反过来可能导致局部和/或广泛的疾病爆发。此外，对更高疫苗储备水平进行适度投资将显著降低此类事件的风险。
