New COVID-19 Strain Is Most Transmissible Yet, Detected In 29 Countries: WHO

A new Covid-19 strain has become the most transmissible and dominant strain in the United States, while 29 other countries have detected the new subvariant, the World Health Organization reported.

In a press conference on Wednesday, health officials said that Omicron strain XBB.1.5 could drive a new wave of cases, but its severity is still unknown.

"We are concerned about its growth advantage, in particular in some countries in Europe and the Northeast part of the United States, where XBB.1.5 has rapidly replaced other circulating sub-variants," Maria Van Kerkhove, WHO's Covid-19 technical lead, said.

"XBB.1.5 has been detected in 29 countries so far. There may be more. As sequencing becomes less and less available at a global level, it is difficult for us to track each of these subvariants of Omicron," Van Kerkhove added.

While new waves of infection are possible because of the latest strain, officials are hopeful that it will not translate to new waves of death because of immunity built up by vaccination and prior Covid-19 infection.

"We do expect further waves of infection around the world, but that doesn't have to translate into further waves of death because our countermeasures continue to work," the expert said.

Symptoms of XBB.1.5 are reportedly similar to those of previous Omicron strains. However, it's still too early to confirm, according to the BBC.

In the U.S., the subvariant went from being present in 4% of sequenced cases to 40% in December, White House Covid-19 Response Coordinator Ashish Jha said in a tweet.

He added that the government has been tracking XBB.1.5 and other variants and providing easy access to updated Covid-19 vaccines.

"If you had an infection before July or your last vaccine was before the bivalent update in September, your protection against an XBB.1.5 infection is probably not that great," he said.

The official added that the possibility of an XBB.1.5 wave would depend on various factors, including the immunity of the population.