The World Health Organization (WHO) and the U.S. Center for Disease Control said on Monday that two new COVID-19 variants are spreading rapidly across the world.
According to WHO they are more dangerous than the original Omicron species and may cause widespread morbidity during this upcoming winter.
U.S. health regulators estimated that BQ.1 and closely related BQ.1.1 accounted for 16.6% of coronavirus cases in the country, nearly doubling from last week, while Europe expects them to become the dominant variants within a month.
The European Centre for Disease Prevention and Control said the variants were likely to drive up cases in the coming weeks to months in the European region.
The two variants are descendants of Omicron's BA.5 subvariant, which is the dominant form of the coronavirus in the United States. Regulators in Europe and the U.S. have recently authorized vaccine boosters that target it.
There is no evidence yet that BQ.1 is linked with increased severity compared with the circulating Omicron variants BA.4 and BA.5, European officials said, but warned it may evade some immune protection, citing laboratory studies in Asia.
"These variants (BQ.1 and BQ.1.1) can quite possibly lead to a very bad surge of illness this winter in the U.S. as it's already starting to happen in Europe and the UK," said Gregory Poland, a virologist and vaccine researcher at Mayo Clinic.
New variants are monitored closely by regulators and vaccine manufacturers in case they start to evade protection offered by current shots.
COVID variants will continue to emerge and spread because viruses—particularly RNA viruses, such as COVID - make many mistakes during their replication. They cannot correct these mistakes, called mutations, and the result is new variants. In fact, the coronavirus has already created hundreds of these mutations.
Reuters contributed to this article.