The Delta variant doubles the risk of hospitalisation but two vaccines still provide strong protection, according to a new study in Scotland.
The variant, which was first discovered in India, has now become the dominant strain of Covid-19 in Scotland.
A research team from the Universities of Edinburgh and Strathclyde and Public Health Scotland analysed data from the start of April until June 6.
It found that the Pfizer-BioNTech vaccine provided 79% protection against the Delta variant at least two weeks after the second dose, compared with 92% against the Alpha variant, first discovered in Kent.
The Oxford-AstraZeneca vaccine provided 60% protection against the Delta variant compared with 73% against the Alpha strain.
Professor Aziz Sheikh, director of the University of Edinburgh’s Usher Institute and EAVE II study lead, said: “Over a matter of weeks the Delta variant has become the dominant strain of SARS-CoV-2 in Scotland. It is unfortunately associated with an increased risk of hospitalisation from Covid-19.
“Whilst possibly not as effective as against other variants, two doses of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines still offer substantial protection against the risk of infection and hospitalisation.
“It is therefore really important that, when offered second doses, people take these up both to protect themselves and to reduce household and community transmission.”
The findings have been published in The Lancet and are preliminary results which the team behind the research hopes other countries will repeat.
They stress that no comparison is being made directly between the effectiveness of the two vaccines.
Professor Chris Robertson, University of Strathclyde, said “It is important to recognise that these are preliminary results using rapidly accessible data.
“A fuller understanding will come when the results presented here are combined with similar analyses from other data sets in the UK”.