STOCKHOLM, Sweden — Omicron subvariant XBB.1.5, which now accounts for a quarter of US COVID-19 cases, could become the dominant strain in Europe within a few months, the EU's disease agency said Friday.
The European Centre for Disease Prevention and Control (ECDC) said that mathematical modelling suggested the subvariant, which is the most transmissible to date, could become the dominant variant in the European Union "after one to two months, given the current low proportions reported in the EU/EEA and its estimated growth rate".
For the general population, the agency said the risk associated with the variant was estimated to be low.
However, the "risk is moderate to high for vulnerable individuals such as the elderly and non-vaccinated and immunocompromised people".
The agency also noted that "several knowledge gaps" existed, meaning the assessment was subject to change in the light of more evidence.
While the subvariant now accounts for more than 27% of infections in the United States, XBB.1.5 was still responsible for fewer than 2.5% of COVID-19 cases in the EU in the last weeks of 2022, according to the ECDC.
"There are currently no signals that the infection severity of XBB.1.5 is different to that of previously circulating omicron sub-lineages," the agency said.
Thirty-eight countries have reported XBB.1.5 cases.
Of those, 82% are in the United States, 8% in Britain and 2% in Denmark, the World Health Organization said in a rapid risk assessment on Wednesday.
According to virologists, the subvariant is very similar to its predecessor, XBB.1, but has an additional mutation to its spike protein -- the key that allows the virus into the body's cells.