Scientists find ‘stealth’ version of Omicron that may be harder to track

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. It came as the number of cases of the original Omicron variant detected in the UK rose by 101 to 437 in a single day and Scotland announced a return to working from home. 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 variant is still detected as coronavirus by all the usual tests, and can be identified as the Omicron variant through genomic testing, but likely cases are not flagged up by routine PCR tests that give quicker results.