In recent days, headlines about a “stealth” Omicron variant have conjured the notion that a villainous new form of the coronavirus is secretly creating a disastrous new wave of Covid.

That scenario is highly unlikely, scientists say. But the new variant, which goes by the scientific name BA.2 and is one of three branches of the Omicron viral family, could drag out the Omicron surge in much of the world.

So far, BA.2 doesn’t appear to cause more severe disease, and vaccines are just as effective against it as they are against other forms of Omicron. But it does show signs of spreading more readily.

Continue reading “‘Stealth’ Variant No Cause for Alarm, but Could Slow Case Decline” →

As nurses and doctors struggle with a record-breaking wave of Omicron cases, evolutionary biologists are engaged in a struggle of their own: figuring out how this world-dominating variant came to be.

When the Omicron variant took off in southern Africa in November, scientists were taken aback by its genetic makeup. Whereas earlier variants had differed from the original Wuhan version of the coronavirus by a dozen or two mutations, Omicron had 53 — a shockingly large jump in viral evolution.

In a study posted online last week, an international team of scientists further deepened the mystery. They found that 13 of those mutations were rarely, if ever, found in other coronaviruses, suggesting they should have been harmful to Omicron. Instead, when acting in concert, these mutations appear to be key to some of Omicron’s most essential functions.

Continue reading “Omicron’s Radical Evolution” →