The Omicron variant of the coronavirus has been detected in 89 countries and is spreading rapidly even in places with high levels of population immunity, the World Health Organisation( WHO) said on Saturday. The number of Covid-19 cases involving Omicron is doubling every 1.5 to three days in countries where there is community transmission of the variant and not just people who were infected abroad, the WHO said. Omicron’s “ substantial growth advantage ” over the Delta variant means it is likel