New Delhi, Aug 18 : After EG.5 raised concerns for a new Covid outbreak, the World Health Organization (WHO) has now flagged another sub-variant of Omicron BA.2.86, dubbed as BA.X. BA.2.86 is from Omicron's BA. 2 lineage and was first detected in Israel. It has to date been detected in just five cases -- in Denmark (2), Israel (1), the US (1), the UK (1) -- and the variant has shown large mutations, increasing fears of fresh Covid cases. After just three cases WHO declared it a variant under monitoring (VUM), and also called for closer monitoring of the variant to understand its spread and severity. 'WHO has designated Covid-19 variant BA.2.86 as a 'variant under monitoring' today due to the large number of mutations it carries,' the global health body wrote in a post on X (formerly known as Twitter),' adding that 'the number of mutations warrants attention'. 'Very limited info available right now but large mutations, needs closer monitoring surveillance, sequencing & Covid19 reporting critical to track known/detect new variants,' added Maria Van Kerkhove, technical lead for Covid-19 response at WHO, in a post Even as Covid virus continues to circulate and evolve, the WHO also called for 'better surveillance, sequencing, and reporting'. 'It seems BA.2.86 is the real thing -- now detected from London, England also. The 5th case in total,' Dr. Vipin M. Vashishtha, member of WHO's Vaccine Safety Net. 'The seriousness of this issue can be gauged that WHO has already declared it a VUM, based on only 3 sequences,' he said. According to Israeli scientist Shay Fleishon, who was the first to flag BA.2.86, the sub-variant is 'wild'. Fleishon from Weizmann Institute of Science said that BA.2.86 was detected 'from a patient which is not chronic nor infected by one (man able to transmit inter host)'. Similarly, the two cases detected in the country were not 'immunocompromised' and had 'no epidemiological link', Denmark's Statens Serum Institute said on X. There is also no indication that the new variant causes severe illness, it added. In the US, the first case of BA.2.86 was reported by a lab at the University of Michigan during "baseline surveillance". The US Centers for Disease Control and Prevention (CDC) on Thursday announced it was tracking the strain. Based on deep mutational scanning, Jesse Bloom, an evolutionary biologist at the Fred Hutch Cancer Centre, said that BA.2.86 variant will have 'equal or greater escape than XBB.1.5 from antibodies elicited by pre-Omicron and first-generation Omicron variants'. The XBB.1.5 subvariant of Omicron, detected earlier this year, had high transmissibility and infectivity. /IANS