Fears Indian Covid-19 variant can infect two hours on

Victorian authorities fear a two-hour gap between an infected person leaving a grocery store and another person entering was enough contact for the virus to spread.

Victoria’s chief health officer Brett Sutton on Wednesday compared the B. 1.617.1 variant to the measles. Picture: Getty Images

Victorian health authorities fear a two-hour gap between an infected person leaving a grocery store in Melbourne’s north and another person entering was enough contact for the Indian variant to jump from one person to another.

Victoria’s chief health officer Brett Sutton on Wednesday compared the B. 1.617.1 variant to the measles and said contact tracers believe someone who visited JMD Spices in Epping contracted the virus two hours after a positive case had left. “They (the positive case) were there for a substantial period of time but they had left two hours before the next exposed individual came in, who’s become a case,” Professor Sutton said.

“That’s in the measles category of infectiousness.”

Victoria recorded six Covid-19 cases on Wednesday after more than 50,000 tests.

A second infected resident at the Arcare aged care facility in the suburb of Maidstone in Melbourne’s northwest will be inclu­ded in Thursday’s case numbers.

One case, from the Surf Coast town of Anglesea, is believed to have contracted the virus at the Brighton Beach Hotel despite having eaten outdoors.

Professor Sutton said this demonstrated the heightened infectivity of the Indian strain, also referred to as the Kappa variant.

“This variant of concern is starting to show up in places where normally it would be less likely,” he said. “So the Brighton Beach Hotel, that was an outdoor dining setting, well ventilated, where we wouldn’t expect transmission to occur.”

But epidemiologists and health academics are split over whether the Kappa variant in Melbourne is significantly more infectious than other Covid-19 strains.

James Wood, who models infectious disease spread, said the reason for the increase in stranger-to-stranger transmission was likely due to better contact tracing rather than a more virulent Covid-19 strain.

“We are tracking down these fleeting moments of transmission that we wouldn’t have tracked last year,” Dr Wood said.

“It’s hard to understand how significant this is, because we don’t measure how many fleeting interactions we make a day, so we can’t make any conclusions.”

There has been a long-running debate about the frequency of aerosol transmission. On Wednesday, Queensland University of Technology physicist Lidia Morawska said the spread of the virus at JMD Spices was not necessarily due to it being more infectious.

“(The virus) can stay in the air for as long as air flow will keep them in the air – be it minutes or hours,” she said.

“The transmission could have happened regardless of how infectious the strain was.”

Professor Morawska’s theory is consistent with findings published in The Australian in May which showed the Holiday Inn Covid-19 outbreak that sparked Victoria’s third lockdown was caused by the lengthy swabbing of an unmasked woman in an open doorway, not from a nearby room of a man using a nebuliser.

“The bottom line is the virus was generated by an infected person, who was breathing, speaking and generating particles all the time. Airflow was what took it to other people outside the room,” Professor Morawska said.

But Raina MacIntyre, a researcher at the Kirby Institute, said the Kappa variant in Melbourne was likely to be just as infectious as its Delta counterpart in Britain — which has been assessed as being 50 per cent more infectious that earlier variants.