So far, much of the pressure to share technology has centered on messenger RNA vaccines, such as those made by Pfizer-BioNTech and Moderna, which are approved in the U.S. and highly effective against Covid-19. The mRNA model also offers the advantage of having a production process that’s simpler than that of some other vaccines and may be quickly adapted to respond to emerging variants of the virus. But the companies that have pioneered the mRNA vaccines have yet to offer to share their knowledge and expertise.

Earlier this month, the World Health Organization established the mRNA technology transfer hub, through which manufacturers of medical products and owners of patented vaccine technology have been invited to provide know-how, process training, and intellectual property rights so that low- and middle-income countries can produce their own vaccines. On Tuesday, Martin Friede, coordinator of the WHO’s Initiative for Vaccine Research, said that the hub had already received some 50 expressions of interest from companies, including some that have patents on components or processes involved in vaccine manufacturing.

But Moderna; BioNTech, the German company that has developed an mRNA vaccine in partnership with Pfizer; and CureVac, another German company that has developed an mRNA vaccine with a longer shelf life, have yet to respond to the call, according to Friede.

Friede emphasized that a lack of know-how, as opposed to patent protections, are the major barrier to expanding production.

Others agree sharing know-how is key — and getting cooperation from the companies that created the mRNA vaccines is necessary before deciding to retrofit or build facilities to make them. “It’s useless to focus on that if BioNTech and Pfizer and Moderna are not going to surrender the information on how to do it,” Edward Hammond, an independent consultant who works on vaccine manufacturing, said in a recent online roundtable about vaccine production capacity. “If it is the case that we don’t have an open and cooperative and productive technology transfer environment, then the capacity situation looks a little bit different because you’re going to be relying on a different set of technologies.”

Scaling up supply to meet the global need will also require overcoming shortages of various components, including the tiny fat droplets that enable the mRNA in the vaccine to enter cells, which may also slow the the process of upscaling production.

Gates suggested that it could be unsafe to share the critical information that allows vaccines to be more widely produced: “There’s only so many vaccine factories in the world, and people are very serious about the safety of vaccines. And so moving something that had never been done — moving a vaccine, say, from a [Johnson & Johnson] factory into a factory in India — it’s novel — it’s only because of our grants and expertise that that can happen at all.” The delay in getting vaccines to low- and middle-income countries, he added, was shorter than expected. “Typically in global health, it takes a decade between when a vaccine comes into the rich world and when it gets to the poor countries.”

Yet, in the past few months, the danger of not transferring the knowledge more quickly has become painfully clear, with deaths climbing in India, Brazil, and other parts of the world that have been unable to procure adequate supplies of vaccines while richer countries stockpile them.

The inequality is only increasing. The state of Florida, which has a population of 21.5 million, has now received some 20 million vaccine doses — more than Covax has delivered to all of Africa, which is home to 1.2 billion people. Worldwide, Covax, which is now supplying vaccines to over 100 economies, has only delivered 49 million doses so far, less than have been distributed in California and Illinois.

Meanwhile, wealthy countries are already in the process of purchasing booster shots. Canada just made a deal with Pfizer to get 35 million doses of boosters by next year, which means they will arrive before most people around the world receive their first shot.