What is the vision of HERMES?
Developed by our HERMES Logistics Modeling Team with funding from the Bill and Melinda Gates Foundation and the National Institutes of Health, HERMES is a software platform that allows users to generate a detailed discrete event simulation model of any vaccine supply chain. This simulation model can serve as a “virtual laboratory” for decision makers (e.g., policy makers, health officials, funders, investors, vaccine and other technology developers, manufacturers, distributors, logisticians, scientists, and researchers) to address a variety of questions such as:
- What will be the impact of introducing new technologies (e.g., vaccines, storage, or monitoring)?
- What the effects of altering the characteristics of vaccines and other technologies (e.g., vaccine vial size, vaccine thermostability, or cold device capacity)?
- How do the configuration and the operations of the supply chain (e.g., storage devices, shipping frequency, personnel, or ordering policy) affect performance and cost?
- What may be the effects of differing conditions and circumstances (e.g., power outages, delays, inclement weather, transport breakdown, or limited access)?
- How should one invest or allocate resources (e.g., adding refrigerators vs. increasing transport frequency)?
- How can vaccine delivery be optimized (e.g., minimize the cost per immunized child or maximize immunization availability)?
HERMES can work on nearly any laptop computer.
How can one generate a supply chain model with the HERMES software?
Figure 1 demonstrates how the simulation model can represent each storage location.
What is the Structure of the Simulation Model?
The model can represent
every storage location (Figure 1), immunization location
(Figure 2), storage device, transport
vaccine vial, and vaccine accessory in a supply chain. The model represents each vaccine vial, diluent vial, or vaccine accessory with an entity, which can assume a variety of characteristics such as type, size, number of doses per vial, temperature profile, age, and expiration date. Millions of different vaccine
vials and accessories can flow through the model simultaneously just like a
real supply chain. There is practically no limit to the number of vaccines,
storage locations, devices, and vehicles that the model can simulate.
Figure 2 illustrates the simulation model’s representation of each immunization location.
What outcomes and measures can HERMES Simulation Models generate?
models are detailed simulations (i.e., virtual
representations), that the user can choose to pull nearly any
type of measure. For example, a user could even track
the daily inventory by vaccine vial type in any individual
refrigerator in the supply chain. Examples of common
model outputs include vaccine availability (i.e., the
percentage of clients arriving at an immunization location
who are successfully vaccinated), vaccine wastage, storage
capacity utilization (i.e., the percentage of available space
used each day), transport capacity utilization, number of
stockouts (i.e., the number of times a location runs out of a
particular vaccine), vaccine doses delivered or administered,
and time-to-patient. The Project OPTIMIZE (also funded
by the Gates Foundation) costing tool can then translate the
relevant HERMES measures into nearly any economic measure of
interest (e.g., cost per dose administered, cost by location,
and cost by activity). HERMES can also generate various
visualizations (examples below).
inventory graphs at some sample Niger locations at different
levels before and after rotavirus (RV)
and pneumococcal (PCV) introductions. The red arrows indicate stock-outs.
visualization depicting maximum storage capacity utilization
(red being the highest and blue being the lowest) at
locations in the country of Benin.