Regulators on Friday authorised another coronavirus vaccine for use in the UK amid concerns about rising COVID-19 cases as a variant of the virus first identified in India spreads around the country.

The Medicines and Healthcare products Regulatory Agency said the single-dose vaccine made by Johnson & Johnson met "the expected standards of safety, quality and effectiveness."

The authorisation takes the number of vaccines in the UK's armory to four following earlier approvals for the two-dose regimens developed by Pfizer/BioNTech, AstraZeneca and the University of Oxford, and Moderna.

The regulator said the vaccine developed by J&J subsidiary Janssen has been shown to be 67 per cent effective overall in preventing COVID-19 infection and 85 per cent effective in preventing severe disease or hospitalization. It can be be stored at refrigerator temperatures of 2 to 8 degrees Celsius (36 to 47 F), which the regulator said makes it “ideal for distribution to care homes and other locations."

The UK has rapidly rolled out vaccines since December. Nearly 58 per cent of the population has received at least one dose and around 35 per cent has gotten two shots.

The UK has seen a modest uptick in new cases in recent days as a result of the variant identified in India, which is considered to be more transmissible than the previously dominant strain of the virus.

On Thursday, the country reported 3,542 new confirmed cases, its highest daily total since April 12. The number of cases remains well below the close to 70,000 recorded in mid-January, during the peak of the second wave.

Concerns are mounting that the next scheduled easing of lockdown restrictions in England on June 21 will have to be delayed if case numbers continue to rise. While the most vulnerable people should have vaccine protection, there are worries the virus could spread widely among younger adults and that many will end up needing to go to the hospital.