Scientists say they have identified a “stealth” version of Omicron which cannot be distinguished from other variants using the PCR tests that public health officials deploy to gain a quick picture of its spread around the world.
The stealth variant has many mutations in common with standard Omicron, but it lacks a particular genetic change that allows lab-based PCR tests to be used as a rough and ready means of flagging up probable cases.
… The stealth variant was first spotted among Covid virus genomes submitted in recent days from South Africa, Australia and Canada, but it may already have spread more widely. Among the few dozen cases identified so far, none are in the UK.
