Everyone aged 56 and over will be invited for jabs this week, NHS England has announced.
Hundreds of thousands of letters for those aged between 56 and 59 began landing on doorsteps on Saturday.
The latest round of invitations comes after eight in 10 people aged 65 to 69 took up the offer of inoculation.
More than 18 million people in England – more than a third of the adult population – have already received a vaccine. Across the UK, more than a million people have received both doses of a Covid-19 vaccine, while almost 21.4 million people have had one dose.
Dr Nikki Kanani, NHS England national medical director for primary care, said: “It is testament to our incredible staff that we can now move on to the next age group. The vaccines are both safe and effective, so if anybody who is eligible hasn’t been vaccinated yet, I’d urge them to go online or call 119 and get themselves booked in.”
Matt Hancock, the Health Secretary, said more than nine in 10 of those aged 65 and over and nearly nine in 10 people who are clinically extremely vulnerable had received a first dose.
He said: “It’s an extraordinary feat and we remain on track to offer a first vaccine to all adults by July 31. We are now inviting people aged 56 to 59 to get their jabs.”
NHS England said: “Vaccinations are now being administered at more than 1,600 sites, including mosques, museums and rugby grounds, with the distribution of centres meaning 98 per cent of the country lives within 10 miles of at least one vaccination service.
“People can use the national booking service to reserve a slot.”