Britain's vaccine rollout is limited by a “lumpy” manufacturing process with production changes by Pfizer and a delay by AstraZeneca that could lead to brief supply disruption, Vaccine Deployment Minister Nadhim Zahawi said.

Zahawi told LBC radio that the United Kingdom was hoping for two million vaccines a week from AstraZeneca but that those numbers will not be reached until mid February. Still, he said the UK was on course to hit its rollout targets.

“It's been a bit lumpy,” Zahawi said of vaccine manufacture. Pfizer will temporarily reduce its deliveries to Europe of its vaccine against Covid-19 while it upgrades its production capacity, according to Reuters.

“There's bound to be delays. Any new manufacturing process has challenges at the outset, it is lumpy, it begins to stabilise and get better and better week in, week out,” Zahawi told the BBC.