New XBB.1.5 coronavirus subvariant ‘most transmissible,’ WHO says
Comment on this story
Comment
World Health Organization officials expressed concern on Wednesday about a new micron subvariant of the coronavirus — its most transmissible yet — while also urging China to be more forthcoming with its data on infections and deaths amid a surge in end there.
The XBB.1.5 subvariant, which has been circulating since at least October and is known to have spread to 29 countries, is the most transmissible version of the omicron variant detected by health officials so far, said Maria Van Kerkhove, technical lead for the response of the organization to COVID. However, she added that there was no indication yet that XBB.1.5 caused more severe disease than other omicron subvariants.
The decline in global coronavirus surveillance, incomplete data from China and an increase in Covid-19 deaths worldwide are worrying, she told a press conference. “It is not just a matter of knowing which variants are circulating. We need the global community to evaluate these, look at mutation by mutation to determine if any of these are new variants that are circulating.”
When should I take omicron booster? Will I need Covid vaccines forever?
Mike Ryan, executive director of the WHO’s health emergencies program, who spoke at the same press conference, said he met with Chinese health officials last week and reiterated concerns about China’s data, including its definition. for a death from Covid-19, which he said is seen as too narrow.
The Associated Press reported last month that only Covid-19 deaths from pneumonia or respiratory failure were counted in China’s official data. Chinese authorities have also stopped tracking asymptomatic cases, according to earlier reports by The Washington Post.
Newly tightened criteria for what China considers a Covid-related death have frustrated health officials abroad as they try to prepare for possible mutations from major outbreaks. It has also raised suspicion that the official death toll and number of infections in the world’s most populous country represent a significant underestimate.
China had at least 120,000 new weekly cases or more in December, according to the WHO. The weekly death toll has hovered between 240 and 440 over that period, according to the figures, despite reports of overflowing hospital wards, funeral homes and crematoria.
“We believe that the current number published by China underrepresents the true impact of the disease in terms of hospital admissions, in terms of ICU admissions and especially in terms of deaths,” Ryan said.
Tedros Adhanom Ghebreyesus, WHO director-general, also urged Chinese officials on Wednesday to provide “faster, more regular and reliable data on hospitalizations” and “more comprehensive real-time viral sequencing”.
Chinese officials have said the dominant version of the coronavirus in China is the omicron BA.5 subvariant, Van Kerkhove told reporters, although she said more sequencing needs to be done there.
BA.5 shares common mutations with the BA.2 omicron subvariant, but each has unique features, according to research done in the UK and Austria and published in the journal Nature last month.
XBB is a recombinant of the BA.2.10.1 and BA.2.75 sublines, according to WHO. It quickly became dominant in the northeastern United States.
Michael Baker, a professor of public health at New Zealand’s University of Otago in Wellington, said it will take “several weeks” to see if XBB.1.5 causes more severe disease than previous versions of the coronavirus because hospitalizations in hospitalizations and deaths occur after an increase in infections and it takes time to measure how many of those illnesses can be attributed to XBB.1.5.
He added that an XBB.1.5 wave seems “likely.”
But even if XBB.1.5 turns out to cause less severe disease, being more infectious is still a concern, Baker said.
“As we have seen with the omicron variant in general, its high infectivity has meant that in many countries it has caused more disease and death than any previous variant,” he said.
