"Today we crossed an important threshold in the UK's national vaccination program", Johnson said on Twitter.
Hospital patients who have confirmed admission to a nursing home, high priority health care workers, and Indigenous adults in remote communities are also now cleared to start receiving initial doses of a COVID-19 vaccine.
Over the weekend, ministers are taking part in a renewed drive to encourage people in the top four priority groups - comprising people aged 70 and over, front-line health and social care workers, care home residents and the clinically extremely vulnerable - to get vaccinated.
Mr Johnson went on: "In England, I can tell you we have now offered jabs to everyone in the first four priority groups, the people most likely to be severely ill from coronavirus, hitting the first target we set ourselves".
The world now needs more doses of COVID-19 vaccines than for any other vaccine in history to inoculate enough people for global vaccine immunity, the report said.
Prime Minister Boris Johnson described it as a "significant milestone" and an "extraordinary feat".
"Every jab in the arm is another step closer to returning to normality in the future and that's why we're now inviting the next priority group to book their appointments", Vaccine Minister Nadhim Zahawi said in a statement.
The figure was reached just over two months after the first jab was delivered in the United Kingdom on December 8.
The country will start administering vaccines from Monday to those aged between 65 and 69 and the clinically vulnerable to Covid-19, with nearly 1.2 million already invited to book their jabs, the state-run National Health Service (NHS) said.
"It would be unusual for them to hand over the raw data, but we looked at a great deal of information in detail in discussion with the Chinese counterparts", said John Watson, an epidemiologist who travelled to China as part of the World Health Organization team.
A group of 63 Conservative MPs sent Johnson a letter calling for an easing of lockdowns, saying their was "no justification" for not lifting all Covid restrictions by the end of April when the government hopes to have vaccinated everyone over the age of 50.
Last month the programme expanded rapidly to include larger vaccination centres, smaller GP-run centres, as well as some pharmacies and hospitals.
"The vaccines are already available.... and they will not stop arriving so that the national vaccination plan does not stop", President Andres Manuel Lopez Obrador said at the news conference in the southwestern state of Oaxaca.
Only two COVID-19 vaccines, the Pfizer-BioNTech and Moderna vaccines produced in Europe, are approved for use in Canada and both companies have come up short in their recent shipments to the country.
Dr Chaand Nagpaul, BMA council chairman, said: "Reaching the 15 million first dose target - ahead of time, and to be the first nation in the European Union to do so - is an extraordinary achievement; we are immensely proud of every single healthcare worker across the country for their dedication and countless hours they have spent protecting patients against this terrible virus".
People wear masks to protect them from the COVID-19 virus in Kingston, Ontario, on February 10, 2021.
"All restrictions remaining after 8 March should be proportionate to the ever-increasing number of people we have protected".
2 winter storms in store this week
However, this activity will not be as widespread as it will be on Monday , and impacts will be limited to confined areas. TUESDAY: Temperatures will remain below freezing on Tuesday so any ice that accumulates will still be causing problems.
Meghan pregnant with baby number 2
A spokesperson for the couple said in a statement: "We can confirm that Archie is going to be a big brother". The royal family also reacted to the news of the Duke and Duchess' miscarriage after the news broke .
The Relationship Between Hormones and Exercise Performance
This article is perfect for anyone who is interested in knowing the connection between hormones and exercise performance. On the flip side, exercising regularly ensures optimal productions and functionality of many hormones in the body.