Two new studies, not yet peer-reviewed, have shown immune evasion is the reason behind the Omicron variant's increased transmissibility.

In many countries it has rapidly surged past other variants to become the dominant SARS-CoV-2 strain.

The two studies show that the variant has achieved success despite causing viral levels in the body that are similar to -- or lower than -- those of its main competitor, the Delta variant, Nature reported.

In the first study by Harvard T. H. Chan School of Public Health in Boston, the researchers studied PCR-test results of nose and throat swabs collected from infected individuals and found that those who had Delta had a slightly higher peak viral load than did those with Omicron.

As a result, Meyer and team in their study measured only viral RNA. They also measured the number of infectious virus particles on swabs collected from a separate group of almost 150 infected people.

This more stringent method found no significant difference between the viral loads of vaccinated individuals infected with Omicron and those infected with Delta.

Further, the team also examined samples from people who had been vaccinated but nonetheless became infected with Delta.

Similarly, Harvard researchers also found that five days after an initial positive test for Omicron, about half of tested individuals had viral loads high enough that they were probably still infectious.

Brad's team also found more variability in viral load in individuals infected with Omicron than in people infected with Delta. "That means there's no clear 'one size fits all' approach," he noted.

(This story was published from a syndicated feed. Only the headline and picture has been edited by FIT)