Indian variant named Delta coronavirus variant doubles the risk of hospitalization compared with the previously dominant variant in Britain, but two doses of vaccine still provide strong protection, a Scottish study found on Monday.
The study suggested the protection from vaccines against the Delta variant, might be lower than the effectiveness against the Alpha variant, first identified in Kent, southeast England.
British Prime Minister Boris Johnson is expected to postpone the ending of COVID-19 restrictions in England on Monday, following a quick rise in cases of the Delta variant, which is also more transmissible than the Alpha variant.
The study, published in a research letter in the Lancet, looked at 19,543 community cases and 377 hospitalizations among 5.4 million people in Scotland, 7,723 cases and 1234 hospitalizations of which were found to have the Delta variant.
Chris Robertson, Professor of Public Health Epidemiology, University of Strathclyde, said that adjusting for age and comorbidities, the Delta variant roughly doubled the risk of hospitalization, but vaccines still reduced that risk.
“If you test positive, then two doses of the vaccine or one dose for 28 days roughly reduces your risk of being admitted to hospital by 70 percent,” he told reporters.
Two weeks after the second dose, Pfizer BioNTech’s vaccine was found to have 79 percent protection against infection from the Delta variant, compared to 92 percent against the Alpha variant. For Oxford-AstraZeneca’s vaccine, there was 60 percent protection against Delta compared with 73 percent for Alpha.
The researchers warned against using the data to compare the vaccines against each other due to differences in the cohorts which received each type of shot, and differences in how quickly immunity is developed with each shot.
They said two doses of vaccine provide much better protection than one dose against the Delta variant, and a delay to easing lockdown in England would help more people get second doses and for their immune responses to build up.