US health officials say that while the Omicron variant of the coronavirus is rapidly spreading throughout the country, early indications suggest it may be less dangerous than Delta, which continues to drive a surge of hospitalisations.
President Joe Biden's chief medial adviser, Dr Anthony Fauci, told CNN that scientists need more information before drawing conclusion's about Omicron's severity.
Reports from South Africa, where it emerged and is becoming the dominant strain, suggest that hospitalisation rates have not increased alarmingly.
"Thus far, it does not look like there's a great degree of severity to it," Fauci said. "But we have really got to be careful before we make any determinations that it is less severe or it really doesn't cause any severe illness, comparable to Delta."
Fauci said the Biden administration is considering lifting travel restrictions against non-citizens entering the United States from several African countries. They were imposed as the Omicron variant exploded in the region, but UN Secretary-General Antonio Guterres has blasted such measures as "travel apartheid".