More than half of people who take a rapid antigen test 5 to 9 days after their first test positive for coronavirus or after developing Covid-19 symptoms have tested positive for an antigen test, According to a new study from the Centers for Disease Control and Prevention.
The discovery raises many concerns about Agency’s revised quarantine guidelinessays that many people with Covid can end their quarantine after five days without testing negative for coronavirus.
A CDC scientist who authored the study said he doesn’t believe the agency’s isolation guidelines need to change. But the results show that many people with the virus can still be infected during this period, the scientists said.
The study “proves what many have suspected: 5 days is not enough for a significant number of people,” Angela Rasmussen, a virologist at the Vaccine and Infectious Diseases Foundation at the University of Saskatchewan, said in a statement. email. “The bottom line,” she added, “is that this should absolutely lead to a change in isolation guidelines.”
The study was conducted after Omicron became the dominant variant in the United States and as cases were increasing nationally. Cases Since then, it has dropped sharplyreduce the risk of infection and the number of Americans living in isolation.
The CDC shortened the quarantine period to 5 days from December 10 when the Omicron variant spread. Many public health professionals Criticize this movenote that people can still be contagious after five days, and allowing them to end quarantine without testing could help the new variant spread more quickly.
Ian Plumb, a medical epidemiologist at the CDC and author of the new study, said that he believes the study “fundamentally supported” the agency’s current isolation guidelines, which claim people continue to take precautions – including wearing a mask and restricting travel – until the full 10 days have passed.
“I honestly don’t think that means the current guidance needs to change,” he said.
Instead, he said, the study supports the idea that antigen tests can be successfully integrated into isolation guidelines.
“I think the biggest takeaway is being able to incorporate antigen tests into isolation guidelines because they provide more information about someone’s potentially infectious risk,” he said.
New research based on people infected with the coronavirus was reported to the Yukon-Kuskokwim Health Corporation, which provides healthcare to rural communities in southwestern Alaska, from January 1. until February 9th.
In early January, Yukon-Kuskokwim issued new isolation guidelines. It recommends that people isolate for 10 days after testing positive for or developing symptoms of the virus. However, people who are asymptomatic or have been symptom-free and have not had a fever for at least 24 hours, on Days 5 to 9 of their quarantine period are eligible for the free Abbott BinaxNOW rapid antigen test. fees, by Yukon-Kuskokwim staff. If they test negative, they can end their quarantine early.
Of the 729 people who had antigen tests done on Days 5 to 9 of the isolation period, 54.3% of them tested positive. The proportion of people who tested positive decreased over time: 67.5% tested positive on Day 5 of the quarantine period, compared with 38.6% on Day 9.
The researchers found that people with symptomatic infections were more likely to test positive on days 5 to 9 than those without symptoms. People who have received the main series of vaccines – two doses of the mRNA vaccine or a single dose of Johnson & Johnson – or have been previously infected with the virus are less likely to receive a positive antigen test result. this time than those who were not vaccinated or previously infected.
“Ultimately, I don’t think this is surprising given the data we are seeing and the general concern from the infectious disease community about withdrawals,” said Saskia Popescu, infectious disease epidemiologist at George. shorten the quarantine period in the face of a new variant. Mason University. “But I think it’s important that we continue to evaluate this, as antigen tests are not a perfect proxy for the infectivity and transmissibility of the virus.”
This finding is consistent with several other recent studies that have not been published in a scientific journal or reviewed by outside experts. In one, researchers discovered that more than 40 percent of healthcare workers are immunized positive for rapid antigen tests on Days 5 to 10 of their illness.
In two other studies, The researchers found that a significant proportion of people with suspected and confirmed Omicron infection still have a higher viral load five days after their first positive test for the virus.
https://www.nytimes.com/2022/02/25/science/cdc-isolation-guidelines.html CDC study raises questions about Agency’s Quarantine Guidelines