The sandwich chain says it saw 'consistent sales growth' in the four months since reopening outlets, but that this had 'slowed' since the end of September.
"It's absolutely right that we take steps to stop the spread of the virus and tackle the new wave of infections," says UK managing director Clare Clough
"We've said all along that it's up to Pret to decide our own future and that we must adapt to the new situation we find ourselves in.
"That's why we have to make these further changes as we continue to transform our business model and prepare for the six months ahead.
"We are doing everything we can to support our team members and to prevent further job losses."
Back in the summer, Pret said the impact of the Coronavirus had set sales back 10 years, with trade across the chain's 367 high street sites down 60% year on year.
With the majority of Pret’s reopened stores running on significantly reduced operating hours, it has also asked staff to work approximately 20% fewer hours than before the pandemic.
As part of the group's strategy to attract more customers post lockdown, Pret launched a coffee subscription service back in September, which gives users up to five ‘barista-prepared’ drinks per day for a fixed monthly price of £20.
On the day if its launch 16,500 people subscribed.
Last month, Pret chief executive Pano Christou said he was currently working to evolve Pret into a 'multi-channel business' with dark kitchens, more suburban sites and a shift into retail all planned.