The prevalence of COVID-19 infections in England has been halved since March in light of the quick rollout of vaccines, but new variants are still posing a threat, according to the results of a closely watched survey released on Thursday.

On Monday, British Prime Minister Boris Johnson gave the green light to hugging and the serving of pints inside pubs from next week after months of tough curbs as he set out the next phase of easing the lockdown.

The REACT study, run by scientists at Imperial College London, found that the number of COVID-19 cases has dropped again with an average of only 1 in 1,000 people contracting the virus.

Health Minister Matt Hancock said “today’s findings demonstrate the impact our incredible vaccination rollout is having on COVID-19 infection rates across the country.”

“We’re going in the right direction but with variants present, we must continue to exercise caution,” Hancock added.

The study however does not cover Wales, Scotland and Northern Ireland, which each have their own case tracking.

The REACT study is one of the biggest coronavirus surveys of its kind in England, with more than 127,000 volunteers tested in England between 15 April and 3 May in the latest round.

In total, national prevalence in England fell to 0.1% from 0.2% in March. The estimated prevalence is similar across regions of England. Infections are highest among 25-34 year olds at 0.21%, and lowest in the over-75s at 0.05%, the study found.

The data revealed that 92% of infections were from the B.1.1.7 variant, first detected in England last year, and 7.7% were from the B.1.617.2 variant, first identified in India.