All over-18s in England will be offered their first dose of a Covid vaccine by July 19 the government has announced, the new target date for ending lockdown.
The previous plan had been to offer all adults a jab by the end of July.
The acceleration of the vaccination programme would see two-thirds of adults offered two doses by the new date.
The prime minister had wanted to remove all social distancing rules on June 21.
But a surge in cases of the Delta variant, first identified in India, has persuaded the government to push back the unlocking until July 19.
In an attempt to win the race between the vaccination programme and the virus, all over-40s will be offered a shorter waiting time between their two doses, with the gap cut from eight weeks from twelve.
Everyone in the first 1-9 priority vaccination groups - detailed below - will also be offered their second dose by July 19.
The nine priority groups for phase one of the vaccine rollout:
1. Elderly care home residents and their carers.
2. All those 80 years of age and over and frontline health and social care workers.
3. All those 75 years of age and over.
4. All those 70 years of age and over and the clinically extremely vulnerable.
5. All those 65 years of age and over.
6. Everyone aged between 16 and 64 with underlying health conditions which put them at higher risk of serious disease and mortality.
7. All those 60 years of age and over.
8. All those 55 years of age and over.
9. All those 50 years of age and over.
Data from Public Health England (PHE) published on Monday suggested two doses are “highly effective” against hospitalisation from the Delta variant.
They analysis by PHE suggested the Pfizer-BioNTech vaccine is 96% effective against hospitalisation after two doses and the Oxford-AstraZeneca vaccine is 92% effective.