new York: Two new studies that have not yet been peer-reviewed show that antigenic escape is the reason behind the increased infectivity of epidemic variants.
The first reported Omicron variant from South Africa and Botswana in late November has been detected in 171 countries so far.
In many countries, it has rapidly surged beyond other subspecies to become the leading SARS-CoV-2 strain.
Two studies show that the variant is successful despite causing viral levels in the body similar to or lower than the major competitor Delta mutant. increase.
Omicron does not release large amounts of virus from infected individuals. The reason for its over-transmission comes from its ability to evade SARS-CoV-2 immunity caused by either vaccination or past infections, said Emily Bruce, a virologist at the University of Vermont in Burlington. Was done.
In the first study by Harvard TH Chan Public Health School in Boston, researchers studied PCR test results for nose and throat swabs collected from infected individuals, with those with Delta more than those with Omicron. We have found that it has a slightly higher peak viral load.
Benjamin Meijer, a virologist at the University of Geneva in Switzerland, said, “Of course, the more contagious you are, the higher the viral load should be.”
As a result, Meyer and their research team measured only viral RNA. They also measured the number of infectious virus particles on cotton swabs collected from another group of about 150 infected individuals. With this more stringent method, there was no significant difference in viral load between vaccinated with Omicron and vaccinated with Delta.
In addition, the team examined samples from people who were vaccinated but still infected with Delta. They found that about half of the samples still carry the infectious virus five days after the individual tested positive, the report said.
Similarly, researchers at Harvard University found that five days after the first positive test for Omicron, about half of the individuals tested had a sufficiently high viral load and were probably still infected.
Guidelines published by the US Centers for Disease Control and Prevention (CDC) are concerned about such results, as people infected with the virus can end quarantine 5 days after a positive test result or the first symptom. increase. Harvard Specialist.
Brad’s team also found that there was greater variation in viral load in individuals infected with Omicron than in people infected with Delta. “That is, there is no clear approach to’one size for everything’,” he says.
https://www.siasat.com/omicrons-immune-evasion-behind-rapid-spread-say-studies-2263254/ Omicron’s antigenic escape behind the rapid spread, according to research