The number of people admitted to hospital or dying from Covid-19 in the UK has been slashed by thousands after ministers delayed the date for lifting restrictions, according to a study.
The modelling, completed by Warwick University and presented to the government’s scientific advisers, also showed vaccines were more effective than thought.
Modellers projected a peak of about 3,000 new hospital admissions per day if ministers went ahead with ending social distancing restrictions on June 21.
That figure has been revised down to a peak of about 1,000 per day after a four-week delay was imposed.
The worst-case projection was based on the assumption that two doses of the Oxford-AstraZeneca vaccine provided between 85 per cent and 90 per cent protection against the Indian variant, while two doses of the Pfizer-BioNTech drug provided between 87 per cent and 91 per cent protection.
According to Public Health England data, two doses of AstraZeneca's vaccine is 92 per cent effective against severe illness, while Pfizer's vaccine is 96 per cent effective.
Prof Andrew Pollard, head of the Oxford Vaccine Group, said the PHE research was “incredibly good news for the months ahead”.
However, it is essential people receive both doses of the vaccine, because one dose provides only about 33 per cent protection.
The PHE research is based on real-world cases and raises the prospect that Prime Minister Boris Johnson can proceed with a full lifting of restrictions on July 19.
The government promised to vaccinate up to 10 million more people during the four-week period.
Separate research by Imperial College London found that case numbers continue to grow across England but the increase is being driven by younger people who are not yet vaccinated.
The R number – the number of people an infected person goes on to infect – was an estimated 1.44.
Of the 108,911 people tested for the study between May 20 and June 7, 135 were positive, about one in 670. This is a 50 per cent increase compared with the study's May 3 findings, when one in 1,000 had the virus.
Prof Paul Elliot, director of the React-1 study, said the distribution of vaccines to younger age groups was key to reducing the spread of the virus.
"We can take quite a lot of comfort from the fact that when we look in the details, it does appear that there is very, very good protection in the older ages, where virtually everyone is double vaccinated," he said.
"The government has clearly announced that they want to vaccinate all adults in the period between now and 19 July .
"That will make a very big difference and increase the total amount of population immunity."