Why vaccine need is not the same as funded demand

The simplest way to size an FMD vaccine market is to multiply a cattle population by a coverage rate and a dose schedule. It is also the fastest way to produce a number that no manufacturer will ever invoice against. The multiplication is arithmetic; the market is institutional.

In our own workspace the default scenario — full coverage of the cattle population at two doses per head — is deliberately labelled a technical scenario rather than a forecast. It answers one narrow question: how many doses would be consumed if every animal in the modelled population were vaccinated to schedule. It does not answer whether anyone intends to do that, is allowed to do that, or can pay for it.

Four filters between need and an order

• Policy eligibility. Not every cattle population is inside a vaccination policy. Countries in later control stages may be phasing vaccination out; free countries may hold no routine programme at all and rely on contingency access instead.
• Programme design. Ring vaccination, targeted vaccination of high-risk production sectors and blanket national campaigns produce dose requirements that differ by an order of magnitude from the same herd.
• Budget. A dose requirement becomes demand only when a ministry, a producer levy or a donor line item pays for it. Funding is annual, political, and frequently partial.
• Procurement capability. Specification, tendering, cold chain and delivery all sit between an approved budget and an administered dose. WOAH's procurement guidance exists because this step routinely constrains volume.

The gap between need and purchase is not measurement error. It is the actual subject.

The 2025 country snapshot in our vaccine workspace makes this concrete. Several endemic countries with very large susceptible populations carry modelled purchases that are a small fraction of modelled need, while countries in advanced control programmes sit close to parity. Those two situations look identical in a herd-size model and are completely different commercially: one is an unfunded requirement, the other is a served market.

What to do with the difference

Treating the unfunded portion as addressable market overstates near-term revenue. Treating it as zero understates the public-health task and the potential effect of a financing mechanism, a regional bank arrangement or a donor-supported campaign. The useful practice is to carry both numbers, label which is which, and be explicit about the mechanism that would convert one into the other.

That is why our figures separate modelled requirement, modelled purchased volume and the residual gap, and never net them into a single headline market size.