PUNE, INDIA – In May, a sealed steel box arrived at the cold room of the Serum Institute of India, the world’s largest vaccine maker.

Inside, packed in dry ice, sat a tiny 1-milliliter vial from Oxford, England, containing the cellular material for one of the world’s most promising coronavirus vaccines.

Scientists brought the vial to Building 14, and began growing billions of cells. Thus began one of the biggest gambles yet in the quest to find the vaccine for COVID-19.

The Serum Institute, which is exclusively controlled by a small and rich Indian family, is doing what a few other companies in the race for a vaccine are doing: mass-producing hundreds of millions of doses of a vaccine candidate that is still in trials and might not even work.

If it does, Adar Poonawalla, CEO and the only child of the company’s founder, will have on hand what everyone wants, possibly in greater quantities before anyone else.

With all hopes pinned on a vaccine, the Serum Institute — which has teamed up with Oxford scientists — finds itself in the middle of an extremely competitive and murky endeavor. To get the vaccine out as soon as possible, vaccine developers say they need Serum’s mammoth assembly lines — each year, it churns out 1.5 billion doses of other vaccines, more than any other company.

Half of the world’s children have been vaccinated with Serum’s products. Scale is its specialty. Just the other day, Poonawalla received a shipment of 600 million glass vials.

Right now it’s not clear how much of the coronavirus vaccine that Serum will produce will be kept by India or who will fund its production, leaving the Poonawallas to navigate a torrent of cross-pressures.

India has been walloped by the coronavirus. It’s also led by a nationalistic prime minister, Narendra Modi, whose government has already blocked exports of drugs believed to help treat COVID-19.

Poonawalla, 39, says that he will split the hundreds of millions of vaccine doses he produces 50-50 between India and the rest of the world, with a focus on poorer countries, and that Modi’s government has not objected to this. But he added, “Look, they may still invoke some kind of emergency.”

The Oxford-designed vaccine is just one of several promising contenders that will soon be mass-produced around the world, before they are proven. Vaccines take time not just to perfect but to manufacture. Live cultures need weeks to grow inside bioreactors, for instance, and each vial needs to be cleaned, filled, stoppered, sealed and packaged.

The idea is to conduct these two processes simultaneously and start production now, while the vaccines are still in trials, so that as soon as the trials are finished — at best within the next six months — vaccine doses will be on hand.

U.S. and European governments have committed billions of dollars to this effort, cutting deals with pharmaceutical giants such as Johnson & Johnson, Pfizer, Sanofi and AstraZeneca to speed up the development and production of select vaccine candidates in exchange for hundreds of millions of doses.

AstraZeneca is the lead partner with the Oxford scientists, and it has signed government contracts worth more than $1 billion to manufacture the vaccine for Europe, the U.S. and other markets. But it has allowed the Serum Institute to produce it as well. The difference, Poonawalla said, is that his company is shouldering the cost on its own.

But Serum is distinct from other major vaccine producers in an important way: It is family run. It can make decisions quickly and take big risks, like the one it’s about to, which could cost the family hundreds of millions of dollars. It The company is steered by two men: Poonawalla and his father, Cyrus, a horse breeder turned billionaire.

More than 50 years ago, the Serum Institute began as a shed on the family’s thoroughbred horse farm. The elder Poonawalla realized that instead of donating horses to a vaccine laboratory that needed serum, he could process the serum and make the vaccines himself.

He started with tetanus in 1967. Then snake bite antidotes. Then shots for tuberculosis, hepatitis, polio and the flu. From his stud farm in Pune, he built a vaccine empire.

Initial trial results of the Oxford-designed vaccine showed that it activated antibody levels similar to those seen in recovering patients.

Serum has already produced millions of doses of this vaccine for research and development. By the time the trials finish, expected around November, Serum plans to have stockpiled 300 million doses for commercial use.

But even if this vaccine fails to win the race, the company will still be instrumental. It has teamed up to manufacture four other vaccines, though those are not being mass produced yet.

And if all of those fail, Adar Poonawalla says he can quickly adapt his assembly lines to manufacture whatever vaccine candidate does work. “Very few people can produce it at this cost, this scale and this speed,” he said.