The Omicron subvariant XBB.1.5 is the most transmissible of the Covid-19 subvariants to emerge so far and has been spreading quickly across the United States. Thirty-eight countries have reported XBB.1.5 cases, of which 82% are in the US, eight percent in Britain and 2% in Denmark, the World Health Organisation said in a rapid risk assessment on Wednesday. The European Union's ECDC health agency said this week that XBB.1.5 accounted for less than 2.5% of cases in Europe. Contagiousness and severityMaria Van Kerkhove, the WHO's technical lead on Covid-19, said this week that XBB.1.5 was the most transmissible form of Covid and clearly has a "growth advantage" over other forms of the virus. It added that the proportion of XBB.1.5 cases had doubled every nine days in the United States.

Source: News 24 January 13, 2023 18:01 UTC