Submitting...Stratus is the latest Covid strain to be on the rise. A new Covid strain has taken off across the UK, now becoming the most dominant strain. XFG, known as Stratus, now accounts for nearly 40% of Covid cases, the latest data from the UK Health and Security Agency (UKHSA) revealed. The new Covid strain, Stratus, is a subvariant of Omicron. You can find out more information about the symptoms of Covid and who is eligible for the Covid vaccine at NHS.UK.