Pfizer Inc. partner BioNTech SE is pursuing all its options to make more COVID-19 vaccine doses than the 1.3 billion the companies have promised to produce next year, according to the German company’s chief executive officer.

The companies will probably know by January or February whether and how many additional doses can be produced, Ugur Sahin said Monday. “I am confident that we will be able to increase our network capacity, but we don’t have numbers yet,” he said in an interview.

Efficacy results of more than 90 per cent and approvals around the world have set off a race between countries for additional supplies of the precious shots, with the U.S. seeking to exercise an option for a hundred million. Most of the doses anticipated for next year -- enough to immunize 650 million people -- have already been spoken for.

More than 2 million people in six countries have already gotten their first shot of the standard two-dose regimen, according to data collected by Bloomberg.

BioNTech is seeking more of the raw materials it needs for its mRNA vaccine, more clean rooms and more cooperation partners, Sahin said. The company also needs additional space to formulate the shots, put them into containers and prepare them for shipping, he said. Pfizer is producing vaccine at three sites in the U.S. and one in Europe, while BioNTech has two manufacturing sites in Germany.

The vaccine’s EU approval and an inoculation campaign set to start there on Dec. 27 promise to further draw on stocks. The partners have already begun shipping shots to the U.K., where Health Secretary Matt Hancock on Monday tweeted that some 500,000 people had gotten their first dose.

New Strain Tests

The shot will probably be effective against the new SARS-CoV-2 strain that has emerged in the U.K., Sahin said. Lab tests of the vaccine’s performance have already been done against 20 mutant versions of SARS-CoV-2; the same tests will now be done against the new U.K. version, and should take about two weeks, he said.

Most vaccines target the spike protein, which allows the virus to enter cells.

“This virus has multiple mutations, but as far as we know, 99% of the spike protein is not mutated,” he said. “Let’s do the experiment and get the result. That’s always the best answer, but I would emphasize just to stay calm.”