Doubts cast on 24-hour turnaround for Indian Covid-19 variant

Public health experts have cast doubt on claims people are spreading the Indian Covid-19 variant infection in less than 24 hours.

Victorian Acting Premier James Merlino says a highly new infectious Covid-19 variant is transmitting at record speeds, but public health experts have case doubt on the claim. Picture: Andrew Henshaw

The more infectious and rapidly transmitted Indian Covid-19 variant is causing havoc across Melbourne, but public health experts have cast doubt on claims people are passing it on within 24 hours of being infected.

University of Melbourne epidemiologist Tony Blakely said virus mutations meant the reproduction rate, or R-rate, of some variants, including the Indian B.1.617, was double that seen at the beginning of the pandemic.

“The current strain that we have in Melbourne is somewhere between about 3.75 and 5 – so, basically between 50 to 100 per cent more infectious,” Professor ­Blakely said. “That sees exponential growth just ramps up.”

Acting Premier James Merlino said one of the core issues facing health authorities was that the time between someone contracting the virus and transmission was “tighter than ever”.

“How long it takes between the onset of symptoms in the first and secondary case is averaging just over a day,” Mr Merlino said. “Now, to put that in some perspective, the usual transmission is about five to six days.”

Professor Blakely said he wasn’t “entirely convinced” by the claim, and Murdoch University Health Sciences professor Jeremy Nicholson questioned the veracity of the statement.

“The virus can’t replicate that much more quickly … it is sort of fixed by human cell biology,” Professor Nicholson said.

He said Australia would need to recalibrate its hotel quarantine system to ensure breaches were mitigated.