Why a dose costs more than its purchase price
A polio vaccine dose is only useful if it reaches a child potent and on time. Many campaigns use oral polio vaccine, which must be kept cold; heat can weaken it before it is administered. That requirement creates a cold chain: refrigerated storage and transport, temperature checks, and backup plans for stretches where electricity or roads are unreliable.
In remote areas, the final leg may involve small vehicles, boats, or carrying insulated containers by hand. Those trips take staff time and fuel, while vaccinators also need training, supplies, and a way to record which children were reached. The expense is not incidental overhead. It is part of delivering an effective dose.
The economics of reaching everyone
Polio campaigns face a difficult financing problem: the payoff from vaccination is shared widely, but the work is local and recurring. A community that reaches high coverage helps protect people beyond its borders, while a missed cluster can allow the virus to keep circulating and threaten gains elsewhere. A country paying for outreach therefore cannot capture all the benefit on its own.
That makes sustained international backing important. Funding can support not only vaccine purchases but also transport, local teams, surveillance for signs of continued transmission, and follow-up rounds where children were missed. If money arrives late or is too limited, organizers may have to scale back the number of teams or visits—precisely where distance and weak infrastructure make coverage hardest to achieve.
The practical measure of a campaign is not how many doses were bought, but whether they reached children in every hard-to-reach pocket. The last isolated settlement can determine whether the virus has nowhere left to circulate.
