The prime minister, who will provide an update on how vaccines will now be rolled out to the next priority groups, is expected to address the nation from Downing Street at 5pm.
He will be joined by NHS England Chief Executive Sir Simon Stevens and Chief Medical Officer for England Professor Chris Whitty.
On Sunday the government announced it had managed to offer first vaccine doses to all those in the top four groups most vulnerable to coronavirus - a day ahead of time, with the target set for February 15.
Mr Johnson hailed the the achievement – just over two months after the vaccination programme delivered its first jab – as a “significant milestone” in the fight against the disease.
The government hopes it can vaccinate all nine of the priority groups by the end of April.
Those in the top four priority groups who have not yet been offered a vaccine are encouraged to get in touch with the NHS to request a jab.
With the mid-February target reached, Mr Johnson, his Cabinet, and advisers will start a review of England's Covid-19 restrictions, with a roadmap out of lockdown due to be set out on February 22.
The priority groups:
1 - Residents in a care home for older adults and their carers (800,000 people) 2 - Those aged 80 and over and frontline health and social care workers (a total of 7.1 million people in this group: 3.3m over 80s, 2.4m healthcare workers, 1.4m social care workers) 3 - Those aged 75 and over (2.3 million) 4 - Those aged 70 and over and clinically extremely vulnerable individuals (3.2 million) 5 - Those aged 65 and over (2.9 million) 6 - All individuals aged 16 to 64 with underlying health conditions which put them at higher risk of serious disease and mortality (7.3 million) 7 - Those aged 60 and over (1.8 million) 8 - Those aged 55 years and over (2.4 million) 9 - Those aged 50 years of age and over (2.8 million)
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