Lauria Donald T, Maskery Brian, Poulos Christine, Whittington Dale
University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Vaccine. 2009 Mar 4;27(10):1609-21. doi: 10.1016/j.vaccine.2008.12.032. Epub 2009 Jan 13.
This article considers the investment case for using the Vi polysaccharide vaccine in developing countries from two perspectives: reducing typhoid cases and limiting new health care spending. A case study is presented using data from South and Southeast Asia. The purpose of the paper, however, is to draw broad implications that may apply to developing countries in general. Typical consumer demand functions developed from stated preference household surveys in South and Southeast Asia are used to predict probabilities of adults and children purchasing typhoid vaccinations at different prices. These functions are incorporated in a formal mathematical model. Using data from the recent literature for South and Southeast Asia for typhoid incidence, Vi vaccine effectiveness, public cost of illness, and vaccination program cost, three mass vaccination policy alternatives are evaluated: charging adults and children different (optimal) prices, charging uniform prices, and providing free vaccines. Assuming differential pricing is politically feasible, different vaccine prices for children and adults would maximize the number of typhoid cases avoided from a mass vaccination program if the public sector faces a budget constraint on spending for the vaccination program. However, equal prices for children and adults produce very similar results, and they might be more readily accepted by the community. Alternatively, if vaccines are free, the number of cases is not significantly reduced compared to either pricing policy, but a large external financial contribution from government or donors would be required. A Monte Carlo simulation explores the effects of uncertain parameters on vaccination program outcomes.
本文从两个角度探讨了在发展中国家使用Vi多糖疫苗的投资情况：减少伤寒病例和限制新的医疗保健支出。文中呈现了一个利用南亚和东南亚数据的案例研究。然而，本文的目的是得出可能适用于一般发展中国家的广泛结论。利用在南亚和东南亚进行的基于陈述偏好的家庭调查得出的典型消费者需求函数，来预测成年人和儿童在不同价格下购买伤寒疫苗的概率。这些函数被纳入一个正式的数学模型。利用来自南亚和东南亚近期文献中关于伤寒发病率、Vi疫苗效力、疾病公共成本和疫苗接种计划成本的数据，评估了三种大规模疫苗接种政策选择：对成年人和儿童收取不同（最优）价格、收取统一价格以及提供免费疫苗。假设差别定价在政治上可行，如果公共部门在疫苗接种计划支出上面临预算限制，那么针对儿童和成年人的不同疫苗价格将使大规模疫苗接种计划避免的伤寒病例数量最大化。然而，对儿童和成年人收取相同价格会产生非常相似的结果，而且可能更容易被社区接受。另外，如果疫苗免费，与任何一种定价政策相比，病例数量不会显著减少，但政府或捐助者需要提供大量外部资金。蒙特卡罗模拟探讨了不确定参数对疫苗接种计划结果的影响。
