Britain on Wednesday became the first Western country to approve a Covid-19 vaccine for general use as it announced a rollout of Pfizer-BioNTech's drug from next week. 

"The government has today accepted the recommendation from the independent Medicines and Healthcare products Regulatory Agency (MHRA) to approve Pfizer-BioNTech's Covid-19 vaccine for use," the department of health said in a statement.

"The vaccine will be made available across the UK from next week," the statement said. Priority groups will include care home residents, health and care staff, the elderly and the clinically extremely vulnerable.

After months of "rigorous" clinical trials and thorough analysis of the data, the MHRA "concluded that the vaccine has met its strict standards of safety, quality and effectiveness", the statement added.

"To aid the success of the vaccination programme it is vital everyone continues to play their part and abide by the necessary restrictions in their area so we can further suppress the virus and allow the NHS (National Health Service) to do its work without being overwhelmed."

Pfizer chairman Albert Bourla said it was a "historic moment in the fight against Covid-19". 

"This authorisation is a goal we have been working toward since we first declared that science will win, and we applaud the MHRA for their ability to conduct a careful assessment and take timely action to help protect the people of the UK," he said.

Pfizer and BioNTech added that they expected further regulatory decisions from other countries "in the coming days and weeks".

The announcement came as England exited a month-long coronavirus lockdown, but most of the country remained under restrictions as a new regional system for cutting infection rates kicked in.

The four-week lockdown, which began in November, was imposed to stop surging rates of infection, ease pressure on health services, and to allow families to gather for Christmas.

Prime Minister Boris Johnson, a Covid survivor, succeeded in winning a vote on the measures in parliament late Tuesday, despite significant opposition within his own Conservative ranks.

"All we need to do now is to hold our nerve until these vaccines are indeed in our grasp and indeed being injected into our arms," he told lawmakers before the vote.

Until then "we cannot afford to relax, especially during the cold months of winter", he warned.