A single shot of the Pfizer or Oxford vaccine offers dramatic protection against hospital admission and severe disease in older people, according to a new study from Public Health England (PHE).
The study, which has yet to be peer-reviewed, included more than 7.5 million people aged 70 and over in England.
The data also shows that infections (where people display symptoms) in the over-70s fall from around three weeks after one dose of both vaccines.
Protection against even developing symptomatic Covid-19 in the first place ranged between 57 and 61% for one dose of Pfizer and between 60 and 73% for the Oxford/AstraZeneca vaccine, the study found.
On top of the protection against symptomatic disease, people who had been vaccinated with one dose of Pfizer had an additional 43% lower risk of emergency hospital admission and an additional 51% lower risk of death, according to the study.
PHE Head of Immunisations Mary Ramsay said that while more work needed to be done to understand the impact on vaccines in reducing transmission of the coronavirus, the effect of the rollout was already apparent.
“This adds to growing evidence showing that the vaccines are working to reduce infections and save lives,” she said.
“While there remains much more data to follow, this is encouraging and we are increasingly confident that vaccines are making a real difference.” Another PHE official said that more work needed to be done to establish the efficacy of vaccines against the so-called Brazilian variant of the coronavirus.
Meanwhile, people who had been vaccinated with one dose of the Oxford vaccine had an additional 37% lower risk of emergency hospital admission, while there is currently insufficient follow-up data to assess the impact on death.
The authors said that “both vaccines show similar effects."
"Combined with the effect against symptomatic disease, this indicates that a single dose of either vaccine is approximately 80% effective at preventing hospitalisation and a single dose of (Pfizer) is 85% effective at preventing death with Covid-19.”
UK Health Secretary Mr Hancock told a Downing Street press conference the study was “extremely good news."