Research conducted in the UK, where the variant accounts
for 99% of new Covid cases, suggests it is about 60% more transmissible than the Alpha variant, which previously dominated. It may also be linked to a greater risk of hospitalisation and is somewhat more resistant to vaccines, particularly after one dose.
“This is the problem with hanging everything on vaccines until you’ve got something near a population immunity threshold … you need a much higher coverage to protect against a variant that’s more transmissible,” said Dr Stephen Griffin, a virologist and associate professor at the University of Leeds school of medicine.
“It just speaks to the fact that we really, really must keep cases down at the same time as rolling the vaccines out.”
The calls for caution come at a time when research in Australia indicates just how easily the Delta variant can potentially spread. Based on CCTV footage, health officials suspect it has been transmitted in “scarily fleeting” encounters of roughly five to 10 seconds between people walking past each other in an indoor shopping area in Sydney in at least two instances.
There were no mask mandates in place in Sydney at the time, and the individuals were unlikely to have been vaccinated given that
less than 5% of the Australian population have received both doses. The city and some surrounding areas entered a strict two-week lockdown on Saturday in an effort to curb the spread of the Delta variant.