Facing a brutal new wave of coronavirus cases,India on Thursday made anyone over 45 eligible for vaccination. But the scramble to vaccinate as many people as possible has also meant sharply curtailing exports.

Why it matters: The hopes of vaccinating the world have largely fallen on the shoulders of India, a vaccine manufacturing powerhouse and home to the world’s largest producer, the Serum Institute.

• Until recently, India was exporting most of the doses it was producing — a mix of donations to neighbors and other friendly nations, sales to countries like Saudi Arabia and the U.K., and contributions to the global COVAX initiative.
• Indian-made vaccines have gone to 82 countries.
• Then, after a long lull, cases began to surge. They are now at their highest point since mid-October and are continuing to climb precipitously.
• Vaccine exports, which had been ramping up, suddenly fell sharply. Rather than supplying the world, the Serum Institute appears to have redirected nearly its entire supply to the homefront.

Driving the news: India has not imposed an export ban and will continue to supply doses, including to COVAX, a government source tells Axios. But given "domestic requirements," the source added, "there is some recalibration of the supply schedules.”

• Another official, speaking to Reuters, put it more bluntly: “Right now we are dealing with an emergency situation. Whatever we have, we will use it,” the official said.
• The government aims to vaccinate a minimum of 400 million people, up from 56 million at present (just 4% of the population), the official told Reuters.

By the numbers: India has exported 6 million doses over the last three weeks, with less than 2 million of those going to the COVAX initiative.

• That’s down from 31 million in the three prior weeks, of which 16 million went to COVAX

That’s a crippling setback for COVAX, which is a critical source of vaccines for low-income countries, particularly in Africa.

• COVAX had expected 71% of its first wave of distribution to consist of AstraZeneca doses produced at the Serum Institute, according to a preliminary forecast.
• A spokesman for Gavi, the vaccine alliance, said shipments expected in March and April had been delayed, and COVAX is now “in talks with the government of India in the hope of ensuring some supplies are completed during April.”

What to watch: If this is anything more than a temporary delay, “that would be catastrophic,” African CDC director John Nkengasong told reporters Thursday. He said Africa would likely fall short of its vaccination targets this year.

The big picture: The world currently has four major sources of vaccines. The U.S. is the second-largest producer, just ahead of India, but isn't exporting at all.

• China is currently the top producer and top exporter, according to Airfinity, focusing less on the domestic rollout in part because the virus remains under control in the country.
• The EU, meanwhile, has exported around 40% of its supply to date, but it's in the midst of a vigorous debate about whether and how to curb exports.