Posted on 08/12/2021 12:11:49 PM PDT by Red Badger
In a leaked report, the Centers for Disease Control and Prevention made a surprising claim about the delta variant of the coronavirus: It "is as transmissible as: - Chicken Pox," the agency wrote in a slideshow presentation leaked to The Washington Post on July 26.
Chickenpox is one of the most contagious viruses known. Each individual can spread the virus to as many as "90% of the people close to that person," the CDC reports.
Is the delta variant that contagious as well?
The short answer is no, says evolutionary biologist and biostatistician Tom Wenseleers at the University of Leuven in Belgium.
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Source: The Lancet (1918 flu, SARS), University of Michigan School of Public Health (COVID-19, ebola, measles), Johns Hopkins University School of Public Health (chickenpox), Proceedings of the National Academy of Sciences (HIV), Tom Wenseleers at the University of Leuven (COVID-19 delta variant), Australian Government Department of Health (mumps)
Credit: Michaeleen Doucleff, Alyson Hurt and Adam Cole/NPR. Icon by Gerard Higgins/The Noun Project.
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"Yeah, I didn't find the CDC's statement entirely accurate," says Wenseleers, who was one of the first scientists to formally calculate the transmission advantage of the alpha and delta variants over the original versions of SARS-CoV-2.
Nonetheless, delta is still highly transmissible, he adds. It's one of the most contagious respiratory viruses that we know of, he says.
Here's why.
When scientists measure a virus's transmissibility, they often use what's known as R0, or "R nought. " It's the number of people a sick person will infect when the entire population is vulnerable to the virus.
"So it's the virus's potential of spreading, given ideal conditions for the virus, when no one has any immunity," says computational biologist Karthik Gangavarapu at the Scripps Research Institute.
For example, the flu has an R0 of about two. Each person infected with flu passes the virus on to two people on average. Some people will infect more than two people, and some will infect fewer. But over time, the average will be about two.
Chickenpox, on the other hand, is way more contagious, Gangavarapu says. Chickenpox has an R0 of about nine or 10. So each person with chickenpox infects about 10 other people on average. Outbreaks are explosive.
For SARS-CoV-2, the R0 has actually risen over the course of the pandemic as the virus evolved. When the coronavirus first emerged in 2019, SARS-CoV-2 was slightly more contagious than flu, Gangavarapu says. "The initial COVID-19 strain had an R0 between two and three."
Then about a year later, the virus began to mutate quickly. The alpha variant emerged, likely in the U.K., and was more transmissible than the original strain. A few months later, the delta variant emerged, most likely in India. It was even more transmissible than alpha.
"For the delta variant, the R0 is now calculated at between six and seven," Wenseleers says. So it's two- to three-times as contagious as the original version of SARS-CoV-2 (R0 = 2 to 3) but less contagious than the chickenpox (R0 = 9 to 10).
So why did the CDC say the delta variant was "just as transmissible as" the chickenpox?
For one, the leaked document underestimated the R0 for chickenpox and overestimated the R0 for the delta variant. "The R0 values for delta were preliminary and calculated from data taken from a rather small sample size," a federal official told NPR. The value for the chickenpox (and other R0s in the slideshow) came from a graphic from The New York Times, which wasn't completely accurate.
"At the end of the day, this delta variant is much more transmissible than the alpha variant," the official added. "That's the message people need to take from this." The official requested anonymity because they were not authorized to speak to the media on this topic.
The difference between an R0 of three and six is massive. For example, with the original strain of SARS-CoV-2, one person would infect about three people, and each of those people would infect three more. So after only two rounds of transmission, cases would rise by nine (3 x 3 = 9). After three rounds, cases would rise by 27 (3 x 3 x 3 = 27). But with the delta variant, the first person would infect six others, who would each then infect six more people. So after two rounds of transmission, cases would already rise by 36 (6 x 6 = 36). After three rounds, cases would surge by 216 (6 x 6 x 6 = 216).
With an R0 of six, delta will be extremely difficult to slow down unless populations reach high levels of vaccination, Wenseleers says. And even then surges in cases will still occur, as is now happening in Iceland and parts of the U.S. The vaccine is less than 90% effective at stopping infections with delta, meaning at least 1 in 10 people could have breakthrough infections. And vaccinated people can still spread the virus. In addition, people who aren't vaccinated have a very high risk of infection, Wenseleers says. "Anyone that chooses not to get vaccinated will in all likelihood get infected by the delta variant over the coming months."
For example, in San Francisco, daily case levels are rapidly rising toward those seen last winter despite the fact that more than 70% of the population is vaccinated, per San Francisco Department of Public Health reports.
Although cases of delta are inevitable, hospitalizations aren't, Wenseleers points out. "As long as people would get vaccinated, then we will not get huge wave of hospitalizations." For example, the city of San Francisco has had 3,041 people hospitalized with COVID-19 since March 18, 2020. Only 16 of them were fully vaccinated.
Some more news about COVID that I don’t believe from a news source I don’t trust.
“San Francisco has had 3,041 people hospitalized with COVID-19 since March 18, 2020. Only 16 of them were fully vaccinated”
Speaking of San Fran sicko....how come the homeless dead of covid aren’t stacking up like cordwood in the gay bay?
No social distancing and I can’t believe that they’re all gettin’ the jab....weird.
In short, we’re getting a lot of positives but the number of people actually seriously ill from COVID is not really that high.
CDC lying again. Even liberal NPR is calling them out.
What’s worse is the CDC relying on the NYT for “facts”.
When you’re sleeping on streets full of shit, a stupid virus ain’t got a chance against your immune system..................
“CDC lying again. Even liberal NPR is calling them out.”
It is more likely they are both lying.
I love the way you put that.
“FECAL / ORAL ROUTE”:
“in San Francisco, daily case levels are rapidly rising toward those seen last winter despite the fact that more than 70% of the population is vaccinated”
“streets full of shit”
That ain’t the only thing full of it.....the Cdc is full of it also
This video (at the point I linked it) shows what NPR is doing. Think of the CDC as the “antithesis” and the comments of NPR as “Synthesis” in this presentation:
https://youtu.be/aOysMK5xK5c?t=3321
The point is made in less than a minute.
And that is EXACTLY what is being attempted here.
Yeah, so let’s take the folks pouring over the border (Who by the way in just one batch 7800 tested positive for Covid) and ship them to cities all over the USA. And when asked for “which cities” they are being shipped to, we are told we don’t need to know that....
Hey, it’s almost like the are MANUFACTURING a crisis....But why would they want the american populace to fear for safety?
Do you know what Maslow’s hierarchy of needs are? Educate yourself.
I answered that question once in a college class as :
Air, food, water, sex, drugs and rock & roll................ The teacher was not amused...............
When covid has weakened most of our population - will China release the final solution? Too bad we don't have some collective group that could protect us...
Gee, I wonder why?.........................
I trust the Freepvaxxer reports.....not! They simply read the CDC and call it proven science.
Stupid teacher. You got it right.
And what is the CFR of the “Delta Variant” compared to the original CV-19?
Does either NPR or the CDC have those figures?
{{{crickets?}}}
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