ROME (AP) — Moderna has no plans to share the recipe for its COVID-19 vaccine because executives have concluded that scaling up the company's own production is the best way to increase the global supply, the company’s chairman said Monday.

In an interview with The Associated Press, Noubar Afeyan also reiterated a pledge Moderna made a year ago not to enforce patent infringement on anyone else making a coronavirus vaccine during the pandemic.

“We didn’t have to do that," Afeyan said. ”We think that was the responsible thing to do.” He added: “We want that to be helping the world.”

The United Nations health agency has pressed Moderna to share its vaccine formula. Afeyan said the company analyzed whether it would be better to share the messenger RNA technology and determined that it could expand production and deliver billions of additional doses in 2022.

“Within the next six to nine months, the most reliable way to make high-quality vaccines and in an efficient way is going to be if we make them," Afeyan said. Asked about appeals from the World Health Organization and others, he contended that such pleas assumed ”that we couldn’t get enough capacity, but in fact we know we can.”

Moderna “went from zero production to having 1 billion doses in less than a year," Afeyan said, referring to the Massachusetts-based company's sprint to develop the vaccine and produce it in large quantities. "And we think we will be able to go from 1 to 3 billion" in 2022.

The COVID-19 vaccine is Moderna's only commercial product. The company announced plans last week to open a vaccine plant somewhere in Africa. Afeyan said he hopes a decision will be made soon on an exact location. Still, it could take years to get the plant up and running.

Afeyan spoke on the last full day of a visit to Italy in which he met Pope Francis, who has appealed for universal vaccine access. He also appeared in Venice to promote a humanitarian prize initiative.