Thread: Corona Virus

Here’s what scientists know about how the coronavirus variant spreads.




Two cases of a new coronavirus variant were discovered in Colorado this week, and two more in California and Florida. Above, people outside in Denver. Credit...Daniel Brenner for The New York Times

A more contagious form of the coronavirus is churning in the United States.
First identified in Britain, the variant already accounts for more than 60 percent of new coronavirus cases in London and its neighboring areas, and there’s worry the variant could further exacerbate cases in the U.S. and place greater strain on an already strained health care system.
A variant that spreads more easily also means that people will need to religiously adhere to precautions like social distancing, mask-wearing, hand hygiene and improved ventilation — unwelcome news to many Americans already chafing against restrictions.

We asked experts to weigh in on the evolving research into this new version of the coronavirus. Here’s what they had to say.

The new variant seems to spread more easily between people.

The new variant, known as B.1.1.7, seems to infect more people than earlier versions of the coronavirus, even when the environments are the same.
Scientists initially estimated that the new variant was 70 percent more transmissible, but a recent modeling study pegged that number at 56 percent. Once researchers sift through all the data, it’s possible that the variant will turn out to be just 10 to 20 percent more transmissible, said Trevor Bedford, an evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle.
Even so, Dr. Bedford said, it is likely to catch on rapidly and become the predominant form in the United States by March.

The variant behaves like earlier versions.

So far, at least, the variant does not seem to make people any sicker or lead to more deaths. Still, there is cause for concern: A variant that is more transmissible will increase the death toll simply because it will spread faster and infect more people.
The routes of transmission — by large and small droplets, and tiny aerosolized particles adrift in crowded indoor spaces — have not changed.

Infection with the new variant may increase the amount of virus in the body.

Some preliminary evidence from Britain suggests that people infected with the new variant tend to carry greater amounts of the virus in their noses and throats than those infected with previous versions.
That finding offers one possible explanation for why the new variant spreads more easily: The more virus that infected people harbor in their noses and throats, the more they expel into the air and onto surfaces when they breathe, talk, sing, cough or sneeze.
With previous versions of the virus, contact tracing suggested that about 10 percent of people who have close contact with an infected person — within six feet for at least 15 minutes — inhaled enough virus to become infected.
“With the variant, we might expect 15 percent of those,” Dr. Bedford said. “Currently risky activities become more risky.”

Scientists are still learning how the mutations have changed the virus.

Each infected person offers opportunities for the virus to mutate as it multiplies. With more than 83 million people infected worldwide, the coronavirus is amassing mutations faster than scientists expected at the start of the pandemic.
The vast majority of mutations provide no advantage to the virus and die out. But mutations that improve the virus’s fitness or transmissibility have a greater chance to catch on.
At least one of the 17 new mutations in the variant contributes to its greater contagiousness. The mechanism is not yet known. Some data suggest that the new variant may bind more tightly to a protein on the surface of human cells, allowing it to more readily infect them.
Muge Cevik, an infectious disease expert at the University of St. Andrews in Scotland and a scientific adviser to the British government, said it’s important to look at evidence “as preliminary and accumulating.”
But one thing is for sure, mitigation efforts will need to remain a priority.
“We need to be much more careful over all, and look at the gaps in our mitigation measures,” said Dr. Cevik said.
— Apoorva Mandavilli

Originally Posted by Arapiles

There's been genuine concern about NSW's "whack a mole" approach for a while: every other State had eliminated the virus, even Victoria, but NSW is acting as a reservoir that has the potential to reinfect other States - which is what happened this time.

Except that last time around Victoria was the reservoir and infected NSW amongst other states. The reality is that Australia cannot realistically expect to eliminate the virus and keep it out. NSW takes the majority of the incoming travellers but Vic, WA and QLD take a number as well, other states less so.
The "whack a mole" approach has worked for the previous two outbreaks in NSW and will work in this one. The Victorian approach also worked but at huge social and financial cost shutting down a state for six weeks. The fear of a large outbreak plunging Victoria intro another lockdown also figures in the mix with the media hysterically pointing to a massive outbreak every time the NSW count goes up by one or two.

I would expect that given previous experience and a 2 week incubation period NSW will continue to have low numbers of new infections for the next couple of weeks at least.

Regards,
Tote