The Omicron variant of coronavirus should not be categorised as “mild”, even as it appears to be less severe than the Delta strain of the disease, World Health Organization Director General Tedros Adhanom Ghebreyesus said on Thursday.

“Just like previous variants, Omicron is hospitalising people and it is killing people,” Tedros said at a media briefing. “In fact, the tsunami of cases is so huge and quick, that it is overwhelming health systems around the world.”

The health body chief noted that last week saw the highest rise in global coronavirus cases in a seven-day period. He added that even these figures were an underestimate as they did not reflect the backlog of testing around Christmas and New Year holidays.

The highly transmissible Omicron variant of coronavirus has led to a huge surge in infections across the world. Last week, around 95 lakh cases were logged globally, an increase of 71% from the previous seven-day period, AFP reported, citing WHO data.

In India too, the cases have gone up alarmingly. On Friday, India reported 1,17,100 new cases as the daily caseload went past the one lakh-mark for the first time since June 6.

While studies have concluded that the Omicron strain was less likely to cause severe disease than the Delta variant, scientists have also stressed that the new variant could spread faster due to a higher number of mutations and its ability to evade the immune response offered by vaccines.

On Thursday, the United Kingdom recorded 1,79,756 fresh Covid-19 cases, a slight decline from Tuesday’ tally when the the country logged the highest-ever daily caseload of more than two lakh. Prime Minister Boris Johnson hit out at those refusing to get vaccinated, describing their campaign as “mumbo jumbo”, The Independent reported.

The United States recorded 6,10,989 new cases on Thursday, a global high. The daily caseload has increased 227% over the last two weeks, according to the New York Times.