With Omicron overtaking Delta as the dominant variant of COVID-19 worldwide, new data shows it's just as serious.
Researchers at Imperial College London compared some 11,000 Omicron cases to nearly 200,000 people infected with other variants, and saw "no evidence of Omicron having lower severity than Delta." That's according to a report issued ahead of peer review.
The report also estimated that the odds of reinfection with Omicron are more than 5 times greater than reinfection with Delta.
Dr. Amesh Adalja of Johns Hopkins University in Maryland says the latest chapter of the pandemic will have two tracks - those who are vaccinated will likely have mild illness, while the unvaccinated will face a high likelihood of needing medical care.
ADALJA: "And that's going to be very difficult for hospitals that are already struggling with Delta COVID-19 patients. So the death toll I think in the end is probably going to be similar to what it would have been with Delta, however, this is going to occur faster because of the way Omicron spreads."
The Omicron variant now accounts for more than 70% of all U.S. coronavirus infections, according to the CDC, with New York City reporting more than 90% of its cases are due to Omicron.
The World Health Organization said COVID-19 cases are now doubling in 1-1/2 to three days in areas with community transmission.
Countries across Europe are imposing new lockdowns as a wave of Omicron washes across the continent.
Israel and the U.S. reported their first deaths from the variant Monday.
Despite an increase in cases, U.S. health authorities are considering reducing the 10-day recommended quarantine period for Americans who test positive for COVID-19, White House medical adviser Anthony Fauci said on CNN Tuesday.
Reducing the CDC's 10-day quarantine recommendation, he said, would help asymptomatic people return to school or work - with the proper precautions - particularly health care workers.