The world needs more than one vaccine to tackle the new coronavirus, even as pharma companies race to be the first with a pandemic shot, said U.S. infectious-disease expert Anthony Fauci.

“I’d love to see more than one vaccine get to the goal line, as it were,” Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said in a BBC radio interview Thursday. “The world needs more than one vaccine.”

Drugmakers such as Pfizer Inc., AstraZeneca Plc, Moderna Inc. and dozens of other biopharmaceutical outfits and academic groups are vying to come up with a safe and effective vaccine against COVID-19. With almost 10.5 million confirmed cases around the globe and over half a million deaths, drugmakers are under increasing pressure to deliver.

Having multiple vaccines will be necessary not just to produce the billions of doses needed to meet demand across the globe. Some drugmakers are focused on specific needs, like making a shot that lasts longer or doesn’t require stringent cold-storage supply chains. And of course there’s the potential for unexpected setbacks or failure.

“You’ve got to be careful if you’re temporarily leading the way versus having a vaccine that’s actually going to work,” Fauci said when asked about one of the most advanced contenders under development from Oxford University and AstraZeneca.

Pfizer and German partner BioNtech SE released some promising results on their experimental shot Wednesday, but any optimism about development advances was doused when U.S. regulators released conditions for vaccine approval. The Food and Drug Administration said any candidate would need to prove itself at least 50 per cent more effective than a placebo to win clearance, rather than merely showing immune-response data. That may delay the first shots to the start of next year, analysts said.