A single dose of the Pfizer and Oxford-AstraZeneca vaccine in patients over 80 years is more than 80% effective at preventing hospitalisation a few weeks after vaccination, according to data by Public Health England. 

In a pre-print of a real-world study, the data also shows symptomatic infections in over 70s decreasing from around three weeks after one dose of both vaccines. There is also evidence for the Pfizer vaccine that suggests it leads to an 83% reduction in deaths from Covid-19.

Since January, protection against symptomatic Covid-19, four weeks after the first dose, ranged between 57 and 61% for one dose of Pfizer and between 60 and 73% for the Oxford-AstraZeneca vaccine.

Dr Mary Ramsay, PHE Head of Immunisation, said that the new analysis adds to growing evidence that the vaccines are working and are highly effective in protecting people against severe illness, hospitalisation and death.

He added: "There remains much more data to follow, this is encouraging and we are increasingly confident that vaccines are making a real difference. It is important to remember that protection is not complete and we don’t yet know how much these vaccines will reduce the risk of you passing COVID-19 onto others."