Next Generation Immunization Supply Chains: Rethinking the Denominator and the Dose
April 25th, 2016 | Viewpoint
April 25th, 2016 | Viewpoint
Today is Innovation Day during World Immunization Week, and there are a lot of innovative ideas out there to reach every child. But innovation doesn’t always require radical new ideas. Sometimes it simply means challenging traditional approaches based on current information. For immunization supply chains, that means changing over 40 years of custom to embrace state-of-the-art commercial best practices.
Imagine a scenario in which a global soft drink company launches a new marketing strategy; it wants 100% of young consumers under five years old in every city, town and village around the world to drink 200 ml of its product at least once a year. The company launches a global advertising campaign and free give-away of their product to the targeted consumers to meet their goal. Imagine the company then produces sufficient quantities, and packages it in 2-litre bottles for supply chain convenience. Calculating 200 ml per person and 100 percent coverage, millions of bottles are distributed to tens of thousands of shops and community marketers based on census figures and catchment area estimates down to the last kilometer. Ethical considerations and community acceptance aside, it would never work from a supply chain perspective, because the population figures and the coverage assumptions are too inaccurate. But that is precisely the model that immunization supply chains have been following for the last 40 years.
The Weakest Link: The problem of the denominator
From the national cold store to the last kilometer, vaccine demand and supply is calculated using a denominator on target population size or, less commonly, expected size of immunization sessions at each vaccination point, then aggregated up the chain. Routine immunization programs are unique in their use of demographic data to operate the supply chain. It’s no secret that the denominator is inaccurate, but immunization experts at every level—including many at the global level—remain wedded to this data point.
The reliance on coverage target data to operate the supply chain is a legacy of data-poor environments. When immunization campaigns were introduced as the primary vehicle to drive coverage, demographic estimates were the only data at hand, and the micro-plan forecast could only be determined based on campaign targets because historical consumption/use data was simply not relevant. But as EPI programs evolved to rely more on routine immunization, they have continued to rely on target coverage resupply forecasts, either because this was the familiar way of doing business, or because they didn’t know or didn’t trust other methods, or because consumption reports from SDPs and vaccinators were simply not forthcoming.
Routine immunization can use routine supply chain data. Almost every other health commodity managed in a well-designed supply chain is resupplied based on reported consumption data, receipts, and remaining stock on hand, with a buffer built in to accommodate demand variability month-to-month. This consumption-based resupply system is designed to ensure a full supply of antiretroviral medicines, antimalarial drugs, contraceptives, and other essential health commodities that must be in full supply. This system is based on the commercial best practice of using point-of-sales data for managing fast-moving consumer products; it works, and it accommodates fluctuations in demand over time. But it only works when national inventories are sufficient to meet demand, and when data are reported from SDPs on time and in full.
If immunization programs continue to rely on inaccurate demographic data to drive the supply chain, no amount of innovation in technology or system optimization is truly going to fix the problem of supply imbalances at the service delivery point.
Unit of measure: doses vs. vials
Another flaw common to immunization supply chains is the use of doses as the unit of measure for managing the supply chain. This is particularly notable at the lower levels of the system, and is related to the previous problem; demand is based on target populations, and each client needs a particular number of doses per antigen. The use of doses rather than vials is attributed to variations in presentation—doses per vial—for the same antigen. For example, DTP comes in single dose, 10-does, and 20-dose presentations, and countries sometimes manage two different presentations of the same antigen in a given year. But managing a supply chain based on doses is a bit like Coca Cola or Pepsi managing beverages based not on various sizes of cans, bottles, and cases but on milliliters of fluid imbibed by the average consumer; it doesn’t happen in the commercial world. Granted, vaccines are different from soft drinks, but best practice is to manage the supply chain based on stockkeeping units (SKUs) which, in vaccine terms, is the vial. Each presentation of each antigen is a unique SKU, so a 10-dose vial of DTP would be a different SKU from a 20-dose vial.
Beyond aligning with commercial and pharmaceutical supply chain best practices, managing by SKU allows supply chain analysts the ability to compare coverage against consumption. Doses administered (coverage) reported via the HMIS can be compared with vials issued (reported via LMIS) to vaccinators to provide an important quality check on coverage reporting, and can also be used to analyze open-vial wastage rates more accurately. Consumption and wastage trends can inform forecasts and procurement specifications, and the right presentation can be targeted to specific SDPs based on their specific trends. Managing by SKU becomes easier—and essential—when barcodes and other technologies are introduced to automate supply chain information systems.
Global and country stakeholders working in immunization are recognizing that immunization supply chains must evolve. Successful supply chains that ensure availability and potency of vaccines and related supplies demand the right data in the right quality at the right time.
Written by Chris Wright