They’ve collectively pledged just over half a billion, and Gavi hopes to add another $1.5 billion in the coming weeks.

Why is something like an AMC necessary? It has to do with the way drug companies price vaccines.

Drug prices are usually set to allow pharma companies to turn a profit after investing in research and development. But vaccines are different: In general, drug companies price vaccines based on what governments will pay for them. Predictably, this translates to wealthier countries paying more for vaccines, and poorer countries paying less. And unless something like an AMC puts an order in ahead of time, that means lower-paying countries can end up at the back of the queue.

Other factors can increase the disparity. If a country is wealthy enough to work directly with a vaccine supplier, they could pay more to get them faster; if AstraZeneca’s vaccine pans out, a $1.2 billion investment means the US will get a hefty chunk of the first billion doses. Other countries may choose to pool their money into a nonprofit like the Pan-American Health Organization or Unicef, which could be cheaper, but slower to deliver.

A successful Covid-19 vaccine may face production bottlenecks, which could drive prices even higher. The World Health Organization says there are just 25 vaccine manufacturing plants that can distribute large quantities across the world, and of those, only some will have the necessary equipment to produce the kind of vaccine that is ultimately successful. And even with sufficient quantities of vaccines in place, there needs to be enough pharmaceutical glass to bottle and distribute it.

This, in theory, is where the Covid-19 AMC will come in. According to Gavi, its goals are to “fund volume guarantees to specific manufacturers for vaccine candidates before they are licensed; commit to market-wide demand guarantees available to any manufacturer; purchase doses when they are licensed and WHO prequalified.” In other words, paying vaccine manufacturers to make sure they provide products for poorer countries.

This tactic has worked in the past: In 2009, Gavi launched its first AMC, for a pneumococcal vaccine. So far, that AMC has saved an estimated 700,000 lives. Without AMCs and other mechanisms in place, poorer countries may be left without vaccines for their residents even after they’re on the market for the rest of the world.

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