People under 40 will be able to being booking their coronavirus vaccines from Thursday morning as the rollout continues.
From tomorrow people aged 38 and 39 will be able to book their covid-19 vaccine.
NHS sources told the PA news agency that the vaccine rollout will continue to younger age groups, with the aim of giving all adults at least once dose by the end of July.
People under 40 are being offered an alternative to the Oxford/AstraZeneca jab, such as the Pfizer or Moderna vaccines.
This is due to the link between the AstraZeneca jab and extremely rare blood clots, including some affecting the brain.
As of Tuesday, 35.6 million first doses of Covid-19 vaccines have been given in the UK, with a further 18 million second doses.
More details on booking vaccinations are expected later on Wednesday.
The news comes after the Prime Minister warned that coronavirus variants could lead to a new wave of disease, worse than the peak of the January wave.
The Prime Minister stressed the need for caution and vigilance as lockdown eased, highlighting particular concern about the Indian variant which experts believe could be even more transmissible than the Kent strain which swept across the UK.
Even without the prospect of a deadly new variant which could escape the vaccines currently being used, Mr Johnson said there was a "high likelihood" of a seasonal surge in coronavirus cases in the winter.
Mr Johnson warned that "new variants pose a potentially lethal danger, including the one first identified in India which is of increasing concern here in the UK".
The European Medicines Agency also said it was "monitoring very closely the data on the Indian variant" but there was "promising evidence" that mRNA vaccines - the types those produced by Pfizer and Moderna - would be able to neutralise it.
In the Commons, Mr Johnson - who has set out plans to ease England's restrictions on May 17 - said "the end of the lockdown is not the end of the pandemic".
He said: "The World Health Organisation has said that the pandemic has now reached its global peak and will last throughout this year.
"Our own scientific advisers judge that although more positive data is coming in and the outlook is improving, there could still be another resurgence in hospitalisations and deaths.
"We also face the persistent threat of new variants and should these prove highly transmissible and elude the protection of our vaccines, they would have the potential to cause even greater suffering than we endured in January."
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