A Downing Street press conference will be held later today as the UK becomes the first country in the world to approve the Covid-19 vaccine from Pfizer and BioNTech.
The Prime Minister will give further details and take questions in the televised briefing from Number 10, which is set to start at 5pm.
Mr Johnson said it is “fantastic” news, tweeting: “It’s the protection of vaccines that will ultimately allow us to reclaim our lives and get the economy moving again.”
The jab has been shown in studies to be 95% effective and works in all age groups.
The UK has ordered 40 million doses of the vaccine, enough to vaccinate 20 million people with two doses, given 21 days apart.
Around 10 million doses are expected to be available for use in the UK in the coming weeks for priority groups, including healthcare workers, with 800,000 doses arriving next week.
A list of who will receive the vaccine first will be set out later on Wednesday.
A Department of Health and Social Care spokesperson said: “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.
"This follows months of rigorous clinical trials and a thorough analysis of the data by experts at the MHRA who have concluded that the vaccine has met its strict standards of safety, quality and effectiveness.
“The Joint Committee on Vaccination and Immunisation (JCVI) will shortly also publish its latest advice for the priority groups to receive the vaccine, including care home residents, health and care staff, the elderly and the clinically extremely vulnerable."
They added: “The vaccine will be made available across the UK from next week. The NHS has decades of experience in delivering large scale vaccination programmes and will begin putting their extensive preparations into action to provide care and support to all those eligible for vaccination.
“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 to do its work without being overwhelmed.
“Further details will be set out shortly.”
