Among the seven cases identified so far, none are in the UK. 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. Researchers say it is too early to know whether the new form of Omicron will spread in the same way as the standard Omicron variant, but that the “stealthy” version is genetically distinct and so may behave differently. The variant is still detected as coronavirus by all the usual tests, and can be identified as the Omicron variant through genomic testing, but probable cases are not flagged up by routine PCR tests that give quicker results. 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 finding 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. Scientists say they have identified a “stealth” version of Omicron that 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.

Pcr 800 amp