Stockpile levels for pediatric vaccines: how much is enough?

In recent years, several factors have led to pediatric vaccine manufacturers experiencing vaccine production interruptions that resulted in vaccine supply shortages. One unfortunate consequence of such events is that not all children in the United States could be vaccinated on time, as set forth by the Recommended Childhood Immunization Schedule, and hence, created the potential for epidemic outbreaks of several childhood diseases. The Centers for Disease Control and Prevention (CDC) have responded to such events by releasing vaccine supplies from the national pediatric vaccine stockpiles, which were designed to mitigate the impact of vaccine production interruptions. This paper analyzes the CDC-proposed vaccine stockpile levels using a stochastic inventory model. The results from this analysis examine the adequacy of the proposed pediatric vaccine stockpile levels, as well as provide insights into what the appropriate pediatric vaccine stockpile levels should be to achieve prespecified vaccination coverage rates. Given that the average pediatric vaccine production interruption has lasted more than 1 year, the model is used to compute appropriate pediatric vaccine stockpile levels sufficient to absorb the effect of such vaccine production interruptions. The level of funding needed to create such pediatric vaccine stockpile levels is also reported.