Although vaccine supply chains in many countries require additional stationary storage and transport capacity to meet current and future needs, international donors tend to donate stationary storage devices far more often than transport equipment. To investigate the impact of only adding stationary storage equipment on the capacity requirements of transport devices and vehicles, we used HERMES (Highly Extensible Resource for Modeling Supply Chains) to construct a discrete event simulation model of the Niger vaccine supply chain. We measured the transport capacity requirement for each mode of transport used in the Niger vaccine cold chain, both before and after adding cold rooms and refrigerators to relieve all stationary storage constraints in the system. With the addition of necessary stationary storage, the average transport capacity requirement increased from 88% to 144% for cold trucks, from 101% to 197% for pickup trucks, and from 366% to 420% for vaccine carriers. Therefore, adding stationary storage alone may worsen or create new transport bottlenecks as more vaccines flow through the system, preventing many vaccines from reaching their target populations. Dynamic modeling can reveal such relationships between stationary storage capacity and transport constraints.
The article discusses a dynamic simulation model of the Niger vaccine supply chain to investigate the impact of adding stationary storage equipment on the capacity requirements of transport devices and vehicles.
Public Health Computational and Operational Research (PHICOR) Group, School of Medicine and Graduate School of Public Health (Mss Haidari, Connor, Wateska, Mueller, Schmitz, and Paul, and Dr Lee), Department of Biostatistics, Graduate School of Public Health (Messrs Leonard and Weng), and Department of Industrial Engineering, School of Engineering (Drs Norman, Rajgopal, Claypool, and Chen), University of Pittsburgh; and Pittsburgh Supercomputing Center (Drs Brown and Welling), Pittsburgh, Pennsylvania.
Correspondence: Bruce Y. Lee, MD, MBA, Public Health Computational and Operational Research (PHICOR) Group, University of Pittsburgh, 200 Meyran Ave, Ste 200, Pittsburgh, PA 15213 (BYL1@pitt.edu).
The HERMES Project team consists of (in alphabetical order): Tina-Marie Assi, PhD, Shawn T. Brown, PhD (Technical Lead), Brigid E. Cakouros, MPH, Sheng-I Chen, PhD, Diana L. Connor, MPH (co-coordinator), Erin G. Claypool, PhD, Leila A. Haidari, MPH, Veena Karir, PharmD, MS, Bruce Y. Lee, MD, MBA (scientific lead), Jim Leonard, Leslie E. Mueller, MPH, Bryan A. Norman, PhD, Proma Paul, MHS, Jayant Rajgopal, PhD, Michelle M. Schmitz, BA, Rachel B. Slayton, PhD, Angela R. Wateska, MPH (co-coordinator), Joel S. Welling, PhD, and Yu-Ting Weng, MS. For further questions regarding HERMES, contact Dr Lee (BYL1@pitt.edu) or Dr Brown (firstname.lastname@example.org).
This work was supported by the Bill and Melinda Gates Foundation via the Vaccine Modeling Initiative and the National Institute of General Medical Sciences Models of Infectious Disease Agent Study (MIDAS). The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data and preparation, review, or approval of the manuscript. No other financial disclosures were reported by the authors of this article.
The authors declare that they have no conflicts of interest.