Jan. 4 (UPI) — Dr. Maria Van Kerkhove said the most dominant subvariant of COVID-19 is also the most transmissible to date.
During a media briefing on Wednesday, the epidemiologist for the World Health Organization said the omicron subvariant XBB.1.5 has been detected in 29 countries, and is possibly in more already. The reason why this strain spreads so easily is because its mutations allow it to quickly infect a host and replicate.
“We are concerned about its growth advantage,” Kerkhove said. “In particular in some countries in Europe and in North America, particularly the northeast part of the United States where XBB.1.5 has rapidly replaced other circulating variants.”
As the virus continues to circulate and become more common, experts worry that it has even more opportunities for future mutations. Kerkhove expects a risk assessment on this subvariant to be published soon.
At the current rate, XBB.1.5 infections are doubling in the United States about every two weeks. The U.S. Centers for Disease Control and Prevention estimates that the subvariant accounted for about 40.5% of COVID-19 cases in the United States as of the end of December. The agency clarified that while it is more transmissible, it is still unclear if its effects are more serious than previous variants.
The WHO risk assessment will further discuss the severity of XBB.1.5.
“We do not have an indication that severity has changed with XBB.1.5,” Kerkhove said.
Kerkhove said it is important to monitor the spread of COVID-19 and development of new variants. WHO has reported more than 13 million cases in the last month, which is believed to be below the true number of cases because reporting has declined in recent months.
“More concerning, we’ve had a 15% increase in deaths in the last month,” she said. “We know that that is an underestimate because there are delays in the reporting.”
While XBB.1.5 takes hold of much of the world, it is not the most dominant strain in China. Most of the COVID-19 infections in the country are of “BA.5 sublineages.” This sublineage makes up about 3.7% of cases in the United States.
