Any chance someone on here can offer some insight on the supposed much faster transmission rate of the Delta variant? There have been some weird stories out there, like how for the original strains it was about 15 minutes of close contact that gives you a big chance of infection, and now there's talk about only 10-15 seconds (!) of close contact being enough. For example:
Queensland’s chief health officer, Dr Jeannette Young, echoed these statements on Wednesday when she announced the state would shut its borders to people from Sydney hotspots.
“With the Delta variant, we’re seeing very fleeting contact leading to transmission,” Young said.
“At the start of this pandemic
, I spoke about 15 minutes of close contact being a concern. Now it looks like it’s five to 10 seconds that’s a concern. The risk is so much higher now than it was only a year ago.”
https://www.theguardian.com/austral...eed-to-know-about-sydneys-delta-covid-variant
In my country all the normally reliable experts are only going as far as saying 'it spreads faster' without making any claims about how much faster exactly, and the Delta variant is currently roughly 5-10% of infections. But if chief health officers from a developed country are making such statements it seems extremely alarming, or am I missing something here?
EDIT: after some searching I think it's the extremely short transmission time in a specific mutation of the (general) Delta variant, called K417N that's being referred to.
https://www.reuters.com/business/he...t-coronavirus-with-k417n-mutation-2021-06-23/
The variant, called "Delta Plus" in India, was first reported in a Public Health England
bulletin on June 11.
It is a sub-lineage of the Delta variant first detected in India and has acquired the spike protein mutation called K417N which is also found in the Beta variant first identified in South Africa.
And some more:
"But, says Ravindra Gupta, professor of clinical microbiology at the Cambridge Institute for Therapeutic Immunology and Infectious Diseases who has been genetically sequencing SARS-CoV-2 and studying its genetic evolution, “I predict 417 is not an important enough mutation. Delta is bad enough as it is and I don’t think 417 will change [it] that much or become dominant.”
That’s because the 417 mutation isn’t new. Gupta says he has also found it in other major variants of the virus, including the B.1.1.7, or Alpha, variant, that was first identified in the U.K., and the B.1.351 or Beta variant first reported in South Africa. “We’ve seen it come up in a number of Alpha isolates and it didn’t take off or anything,” he says.''
https://time.com/6075858/delta-plus-variant/