featureless wrote: Fri Jul 30, 2021 9:13 am
‘The war has changed’: Internal CDC document urges new messaging, warns delta infections likely more severe
Elsewhere, I'd read it described as the original strain had an R0 of 2 (1 infected passed it on to 2 people. Delta has and R0 of 8-9 (one person passes it on to 8 or 9 people.
The delta variant of the coronavirus appears to cause more severe illness than earlier variants and spreads as easily as chickenpox, according to an internal federal health document that argues officials must “acknowledge the war has changed.”
vaccinated individuals infected with delta may be able to transmit the virus as easily as those who are unvaccinated. Vaccinated people infected with delta have measurable viral loads similar to those who are unvaccinated and infected with the variant.
“I think the central issue is that vaccinated people are probably involved to a substantial extent in the transmission of delta,” Jeffrey Shaman, a Columbia University epidemiologist, wrote in an email after reviewing the CDC slides. “In some sense, vaccination is now about personal protection — protecting oneself against severe disease. Herd immunity is not relevant as we are seeing plenty of evidence of repeat and breakthrough infections.”
https://www.washingtonpost.com/health/2 ... -guidance/
“We really need to shift toward a goal of preventing serious disease and disability and medical consequences, and not worry about every virus detected in somebody’s nose,” Neuzil said. “It’s hard to do, but I think we have to become comfortable with coronavirus not going away.”
One wonders about the mutations occurring within the vaccinated...
Yes, it's a powerful variant. From another article on the CDC document.
The highly transmissible Delta variant is a more formidable foe than previously believed, largely due to its ability to infect and be spread by people who are fully vaccinated, according to data gathered by the Centers for Disease Control and Prevention.
A confidential document prepared by the agency cites evidence from a recent outbreak in Massachusetts involving at least 145 people who were infected with the Delta variant, which was first detected in India. In the Massachusetts outbreak, the viral loads of the 80 people who were vaccinated were essentially the same as the viral loads of the 65 people who were not vaccinated.
The CDC document also cites reports about so-called breakthrough cases in India. The viral loads of vaccinated people who nonetheless became infected with Delta were higher than the viral loads of vaccinated people who were infected with other coronavirus strains, those reports found.
The Delta variant was already known to be about 50% more transmissible than the Alpha variant, which was first detected in the United Kingdom and is itself about 56% more transmissible than the original coronavirus that sparked the global pandemic.
Scientists have also established that people infected with Delta have about 1,000 times more viral particles in their upper respiratory systems than people who are infected with earlier coronavirus strains.
That difference allows Delta to jump from person to person just four days after an initial infection, said Chunhuei Chi, director of the Center for Global Health at Oregon State University. With previous strains, it took about six days for that to occur, he said.
This rapid spread helps explain why the Delta variant, which is thought to have arrived in the U.S. in March, now accounts for an estimated 82% of recent coronavirus infections in the United States, according to CDC estimates.
The CDC document suggests that breakthrough cases are expected to rise — not only because of Delta’s enhanced transmission powers, but because the number of vaccinated people is rising as well.
The CDC document cites three reports that link the variant with more serious health outcomes:
In a preprint study from Ontario, Canada, people infected with Delta were more than twice as likely to be admitted to the hospital, nearly four times more likely to be treated in the intensive care unit, and more than twice as likely to die of COVID-19 compared with people infected with earlier versions of the coronavirus.
In a preprint report from Singapore, people infected with Delta were 4.9 times more likely to require oxygen treatment, be admitted to an ICU or die of COVID-19 than were people infected in the initial months of the pandemic.
In a peer-reviewed study from Scotland, the odds of needing hospital care were 85% greater for people with Delta infections than for people infected with other versions of the virus.
In another potentially ominous sign, the CDC document also noted that among people who had already weathered a coronavirus infection at least 180 days earlier, the risk of a subsequent infection with the Delta variant was about 46% higher than the risk of a subsequent infection with the Alpha variant.
Studies from Britain, Canada and Israel suggest the Pfizer-BioNTech vaccine loses some effectiveness when it goes up against Delta. Although its ability to reduce the risk of coronavirus infections and COVID-19 cases was diminished, the vaccine was highly effective at reducing the risk of hospitalization — by 96% in England and Scotland, by 100% in Canada and by 93% in Israel.
Overall, the COVID-19 vaccines authorized for use in the U.S. are making an impact, the CDC document says.
https://www.latimes.com/science/story/2 ... ta-variant
But with only 49.4% of the U.S. population fully vaccinated, other measures are necessary to curb the Delta variant’s spread, the CDC document says.
“Given higher transmissibility and current vaccine coverage, universal masking is essential to reduce transmission of the Delta variant,” it says.
"Everyone is entitled to their own opinion, but not their own facts." - Daniel Patrick Moynihan