The CEO of the Serum Institute of India, the world’s largest maker of vaccines, asked President Biden on Friday to lift a U.S. export embargo on raw materials for vaccines, saying it is hampering vaccine production in other parts of the world.

Why it matters: Equitablyproducing and distributing coronavirus vaccines may be the defining global challenge of 2021 and a crucial step to controlling the pandemic, as prolonged unequal access to vaccines may allow the virus to spread and dangerously mutate in unvaccinated parts of the world.

Context: The Serum Institute of India is also a key supplier of the United Nations-back COVAX facility, which was created to help pool global resources to produce and offer vaccines to all countries regardless of their wealth.

What they're saying: "If we are to truly unite in beating this virus, on behalf of the vaccine industry outside the U.S., I humbly request you to lift the embargo of raw material exports out of the U.S. so that vaccine production can ramp up," Adar Poonawalla, CEO of the Serum Institute of India, said.

• Poonawalla previously told AP that the unavailability of these raw materials could delay the production of the COVID-19 vaccine developed by Novavax by five to six months.
• Serum Institute and Novavax agreed to supply 1.1 billion doses of the vaccine to COVAX, though the company announced in March that it was forced to pause exports to COVAX because of a massive surge in cases in India.\

The big picture: 10 U.S. senators sent a letter to the White House on Thursday night urging Biden to back India and South Africa's appeal to the World Trade Organization to lift intellectual property rules for vaccines, AP reports.

• The temporary waiver, supported by more than 100 countries, may allow nations that are struggling to inoculate their populations to manufacture vaccines faster.

Go deeper: India's second wave hits the whole world through vaccine export curbs