The delta variant is more contagious, more likely to breach protection offered by vaccines and may cause more serious illness than all other known versions of the virus, according to an internal presentation circulated within the Centers for Disease Control and Prevention.
Dr.. Rochelle B. Walinsky, director of the agency, confessed on tuesday That people vaccinated with so-called delta variant superinfection carry the same amount of virus in the nose and throat as unvaccinated people, and may spread it just as quickly, if fewer times.
But the internal document lays out a broader and darker view of the variable.
The delta variable is more than that It is transmissible from the viruses that cause Middle East respiratory syndrome, SARS, Ebola, the common cold, seasonal flu, and smallpox, and is as contagious as chickenpox, according to the document, a copy of which was obtained by The New York Times.
The document said the agency’s immediate next step was to “recognize that the war has changed.” Its contents were first mentioned Written by The Washington Post on Thursday evening.
A federal official who has seen the research described in the document said the tone of the document reflects concern among CDC scientists about the spread of Delta across the country. The agency is expected to release additional data on the alternative on Friday.
“The CDC is very concerned about the data coming in that Delta poses a very serious threat that requires action now,” the official said.
There were an average of 71,000 new cases per day in the United States, as of Thursday. New data suggests that vaccinated people spread the virus and contribute to these numbers – although perhaps to a much lesser extent than unvaccinated people.
Dr. Walinsky described transmission by vaccination as a rare event, but other scientists have suggested it may be more common than previously thought.
The agency’s new guidelines for concealing vaccinated people, which were introduced on Tuesday, were based on information provided in the document. The CDC has recommended that vaccinated people wear masks indoors in public places in communities with high transmission rates of the virus.
But the internal document hints that even this recommendation may not be enough. “Given the high transmissibility and current coverage of the vaccine, comprehensive masking is essential,” the document said.
Agency data suggests that people with weakened immune systems should wear masks even in places where there is no significant transmission rate of the virus. So Americans who are in contact with young children, the elderly or people at risk should be vaccinated.
There are approximately 35,000 symptomatic infections per week among the 162 million Americans who have been vaccinated, according to data collected by the CDC as of July 24 and cited in the internal presentation. But the agency doesn’t track all cases of mild or asymptomatic infections, so the actual incidence may be higher.
The document indicated that infection with the delta variant produces amounts of virus in the airways ten times higher than what is observed in people with the alpha variant, which is also highly contagious.
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The amount of virus in a person infected with Delta is A more than a thousand times Which is seen in people infected with the original version of the virus, according to a recent study.
The CDC document is based on data from multiple studies, including an analysis of the recent outbreak in Provincetown, Massachusetts, which began after the city’s Fourth of July celebrations. By Thursday, that group had grown to 882 cases. Local health officials said about 74 percent have been vaccinated.
Detailed analysis of the spread of cases showed that delta infected people carry massive amounts of the virus in their nose and throat, regardless of their vaccination status, according to the CDC document.
“This is one of the most impressive examples of citizen science that I’ve seen,” said Dr. Celine Gunder, an infectious disease specialist at Bellevue Hospital Center in New York. “The people involved in the Provincetown outbreak were meticulous in making lists of their contacts and exposures.”
The document indicated that infection with the delta variant would likely lead to severe disease. Studies from Canada and Scotland have found that people with the variant are more likely to be hospitalized, while research in Singapore has indicated that they are more likely to need oxygen.
However, Centers for Disease Control and Prevention figures indicate that vaccines are highly effective in preventing serious illness, hospitalization and death among vaccinated people, experts said.
“Overall, delta is the worrisome variant that we already knew about,” said John Moore, a virologist at Weill Cornell Medicine in New York. “But the sky is not falling and vaccination still strongly protects against poor outcomes.”