XBB1.5: Here’s what we know about the ‘most transmissible’ COVID strain yet – National
XBB.1.5, a new COVID-19 strain that has been spreading rapidly in the United States is now the “most transmissible subvariant that has been detected yet,” the World Health Organization says. The subvariant of Omicron has been detected in 29 countries to date, the WHO said during a briefing Wednesday.It is now responsible for approximately 70