Background: Although single-dose vaccine vials were introduced to minimize open vial wastage and contamination, they require more storage space and therefore may have problematic effects on vaccine supply chains.
Objectives: Thailand’s interest in introducing a new single-dose presentation of measles-mumps-rubella vaccine presented an opportunity to explore the supply chain effects of switching a multi-dose vaccine to a single-dose.
Methods: We developed two computational models of the Trang province vaccine supply chain to simulate switching the first dose of the ten-dose measles vaccine to a single-dose measles-mumps-rubella vaccine for children <1 year.
Results: Transport from the region to the province and from the province to the district have ample capacity and are relatively unaffected by the switch. However, transport utilization from the district to sub-district levels increases from an average of 24% (range:8%-58%) to 34% (range:8%-84%). Provincial-level storage utilization increases from an average of 88.7% to 99.9% and some district storage utilization increases from an average of 44.0% (range:16.2%-75.6%) to 57.2% (range:21.3%-99.3%). Additionally, the added disposal and administration costs of single-dose vials could be greatly offset by the cost savings offered from eliminating open vial wastage. Lastly, our study presented a unique unanticipated finding; the policy of ordering vaccines without buffer can be a major factor in the ability to supply all patients. Utilizing single-dose vials eliminates an inherent buffer provided by a ten-dose vial and may not provide enough additional vaccine stock if demand is greater than anticipated, which could ultimately decrease the number of patients served.
Conclusions: When considering switching to single-dose vials, decision makers should consider both the ability of the supply chain to accommodate the added volume as well as vaccine ordering policy to ensure equal vaccine availability. This study emphasizes the importance of modeling impacts prior to vaccine program changes.