A British epidemiologist says the Delta Covid-19 variant, first identified in India, is believed to be 60 per cent more transmissible than the Alpha variant discovered in the UK.
It comes as British Prime Minister Boris Johnson announced England’s lockdown would be extended by another month as cases of the Delta variant continue to climb.
Neil Ferguson of Imperial College London said modelling showed any third wave of Covid-19 infections from the Delta variant could rival Britain’s devastating second wave in January, which was largely made up of cases of the Alpha variant.
Data also showed more than a quarter of those who died from the Delta variant in England were fully vaccinated.
"It's well within possibility that we could see another third wave at least comparable in terms of hospitalisations," Ferguson told Reuters.
"I think deaths probably would be lower, the vaccines are having a highly protective effect ... still it could be quite worrying. But there is a lot of uncertainty."
British researchers are warning mild cases of the Delta variant feel much more like a bad cold. Headaches, sore throats and runny noses are the most commonly-reported symptoms.
Eighteen Delta cases have been identified in New Zealand's MIQ facilities.