In Horsham, there have been four confirmed Omicron cases while there has been one S-gene dropout case. About one in every six positive PCR tests are sent for genome sequencing to determine which variant they are - a process which can take many days. A quicker way to spot potential Omicron cases is to look for a marker called the S-gene, which is missing in variants such as Omicron and Alpha but present in Delta cases. Once identified, swabs showing so-called ‘S-gene dropout’ can then be sent for definitive testing for Omicron. In Mid Sussex, there have so far been no confirmed Omicron cases but there have been five S-gene dropout cases.