The World Health Organization said on Tuesday that as many as 500,000 deaths due to COVID-19 have been recorded since the Omicron variant was declared a variant of concern in late November, terming the tally "beyond tragic".

The WHO's incident manager Abdi Mahamud said that 130 million cases have been recorded globally since Omicron has rapidly overtaken Delta as the world's dominant Covid variant because it is more transmissible, though it appears to cause less severe illness.

"In the age of effective vaccines, half a million people dying, it's really something," Mahamud told a live interaction on the WHO's social media channels.

"While everyone was saying Omicron is milder, they missed the point that half a million people have died since this was detected,” he added.

Maria Van Kerkhove, the WHO's technical lead on COVID-19, said the sheer number of Omicron cases was "astounding", while the true number of cases and deaths would be much higher than just those known about.

"We're still in the middle of this pandemic. I hope we're getting closer to the end of it," she said. "Many countries have not passed their peak of Omicron yet."

"This virus continues to be dangerous," she said.

The WHO is tracking four sub-lineages of Omicron. While the BA.1 sub-strain was dominant, BA.2 is more transmissible and is expected to account for an increasing share of Omicron cases.

Though considered milder than other coronavirus variants, Omicron has infected so many people that it has driven the number of daily deaths beyond where it was last spring, before vaccines were widely available, according to a report in the Washington Post.

Omicron has been particularly lethal to people over 75, the unvaccinated and the medically vulnerable, according to doctors and public health officials.

“Even if on a per-case basis fewer people develop severe illness and die, when you apply a small percentage to a very large number, you get a substantial number,” the Washington Post cited Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, as saying.

The seven-day average of deaths during the omicron surge has reached 2,600 in recent days, climbing past the late September peak of about 2,000 average daily fatalities during the surge of the more dangerous delta variant, according to Washington Post data for the USA. The ranks of hospitalized patients with covid-19 reached record highs in January.

Also read: Indian scientists develop better technique to detect Covid-19