The number of new cases of coronavirus jumped about 55% in the past week, although the number of deaths remained stable, the World Health Organization said.

In a weekly report, WHO said there were about 15 million new cases of COVID-19 and more than 43,000 deaths last week. Every region of the world reported an increase in COVID-19 cases except Africa, where officials noted an 11% decline.

Last week, the WHO noted a record high of 9.5 million new cases of the pandemic in a single week, calling it a "tsunami."

The WHO said that the highly contagious Omicron variant continues to define the pandemic worldwide and is now displacing the previously dominant delta variant. Omicron, which was first detected in southern Africa in late November, makes up nearly 59 percent of all cases.

The WHO said there is growing evidence that Omicron can evade immunity. Numerous studies have been conducted that it is less serious than previous variants.