Modular vaccine packaging increases packing efficiency
Introduction
Currently, individual vaccines vials and their component packaging vary significantly in overall length, width, and height. This is because the vaccine packaging size is determined by the dimensions of both individual cylindrical vials (each containing one or more doses of vaccine) and rectangular inner packs that typically contain 10, 20, 50 or 100 vials of a particular vaccine. The variability of inner pack and vial dimensions may hinder efficient vaccine distribution because it constrains packing of cold boxes and vaccine carriers to quantities that are often inappropriate or suboptimal in the context of country-specific vaccination guidelines. In particular, estimating storage space requirements is more difficult with non-standard sizes and in a resource constrained system it may not be possible to take all the vaccines needed in a carrier because of the inefficient packaging. Modularized packaging is one way to address this because the consequent increase in packing efficiency has the potential to reduce storage space requirements and replenishment frequencies. The standardization of packaging also has the benefit of making operations much simpler for personnel since vaccines can be more easily packed and space requirements can be more easily estimated. While vaccine vial size has been a recent topic of academic and policymaker interest, explorations of alternative packing configurations have not yet addressed inner packs [1], [2], [3], [4], [5], [6], [7], [8], [9], [10]. The packing analysis in this paper proposes that a solution to inefficient packing caused by inner pack and vial size variability is a modular packing system (where vial and inner pack dimensions are more consistent between different vaccines) that allows for more effective packing into cold boxes and vaccine carriers.
Section snippets
Methods
We developed in Microsoft Excel (Microsoft Corp.) a spreadsheet model that evaluated the impact of different packing schemes for the Benin routine regimen plus the introduction of the Rotarix vaccine. The Benin routine vaccine regimen includes Bacillus Calmette-Guerin (BCG), Tetanus, Measles, Oral Polio, Yellow Fever, Diphtheria–Tetanus–Pertussis–Hepatitis B–Haemophilus influenzae type B (DTC–HepB–Hib), Pneumococcal Conjugate (PCV13), and Rotavirus (Rota) vaccines. Specifically, we used the
Conventional packing efficiency
The number of children who can be fully vaccinated with each vaccine type for the conventional inner packs is shown in the bottom row of Table 2 and the maximum expected FIC served by a single storage device is 123. The resulting configuration of inner packs within the device is illustrated in Fig. 2a.
Currently, the FIC-optimizing configuration of conventional inner packs occupies 16.71 liters, representing 81.93% of the available volume of the RCW25; we refer to this as the volume efficiency
Discussion
The results of our study show that the modular inner packs permit more vaccines to be stored in the storage device. This follows from the fact that we choose to standardize vial diameters and inner pack sizes which in turn leads to easier and more efficient packing in a vaccine carrier. Under the current situation with widely varying inner pack sizes it is not possible to arrive at a consistent, space-efficient, packing arrangement. Additionally, the modular inner packs would actually provide
Limitations
While our analysis suggests that modular packaging systems offer benefits over conventional vaccine packaging in the form of increased potential FICs, higher packing densities, and simplifying the process of a worker packing a storage device, there are several limitations to our study. First, the only packing device considered was the Dometic RCW25. While this is a very commonly used cold storage transport device (found in over 100 countries), there are several other such devices available, and
Conclusions
Our analysis suggests that modular packaging systems could offer significant advantages over conventional vaccine packaging systems with respect to space efficiency when combined with a reasonable packing method such as the layer or tower method, when they are stored in standard vaccine carrying devices. This allows for more vaccines to be stored within the same volume while also simplifying the procedures used by field workers for packing storage devices. Ultimately, this could be a simple way
Conflict of interest statement
The authors declare that we have no conflicts of interest.
Acknowledgements
Our HERMES Logistics Modeling Team would like to acknowledge the valuable contributions of Andrew Garnett, consultant to the World Health Organization (WHO), and Dmitri Davydov and Osman Mansoor of UNICEF. This work was supported by the Bill and Melinda Gates Foundation via the HERMES grant, UNICEF, the Agency for Healthcare Research and Quality (AHRQ) via grant R01HS023317, the National Institute of Child Health and Human Development (NICHD) and the Global Obesity Prevention Center (GOPC) via
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