Behind Omicron’s rapid spread are a set of mutations that give it an edge over older variants.
Among Omicron’s roughly 50 mutations, at least 30 are on the spike protein, the structure that helps the virus infiltrate cells and that is also the main target of vaccines.
Lab tests in South Africa, Sweden, the U.K. and the U.S. have shown that antibodies’ ability to prevent the variant from entering cells is weaker than with other strains, giving Omicron a much better shot at infecting people who have been vaccinated or infected previously. That means it can spread rapidly even in highly vaccinated populations.
“If the virus is able to partially evade the immune response induced either by prior infection with another variant or by vaccines, then it will be able to infect and spread more efficiently. This is what we are seeing with the Omicron variant,” said Lawrence Young, a virologist and professor of molecular oncology at the University of Warwick.
A growing body of evidence suggests Omicron’s mutations may also give it inherent transmission advantages in addition to its ability to evade the body’s immune responses.
