Omicron variant, which has driven the latest surge in Covid-19 infections across the world, contains similar or even lower levels of viral load as Delta, according to two new studies.
Yet to be peer-reviewed, the studies suggest that the best explanation for Omicron's lightning-fast spread is its ability to evade immunity – either natural or generated by past vaccination. What is viral load? It is the amount of the virus in an infected person, which is revealed by the CT value of an RT-PCR test.
The viral load, the lower the value, the higher the viral load is. To compare the viral loads of the two variants, researchers studied the PCR test results of the nose and throat swabs collected from infected individuals and found that those who had Delta had a slightly higher viral load than those who had Omicron. “I was really not expecting to see that," said Yonatan Grad, an infectious-disease specialist at the Harvard TH Chan School of Public Health in Boston, Massachusetts.
To ascertain that the findings are true, Benjamin Meyer, a virologist at the University of Geneva in Switzerland, and his colleagues measured the number of infectious virus particles on swabs collected from a separate group of almost 150 infected people.