The Omicron variant of COVID-19 appears to be a less severe disease than the Delta strain, but it does not mean it should be categorized as "mild", World Health Organization (WHO) director-general Tedros Adhanom Ghebreyesus said on Thursday.

During a press briefing, the head of global health body said that at present, 109 countries would miss out on fully vaccinating 70 per cent of their populations by the start of July 2022. "Last week, the highest number of COVID-19 cases were reported so far in the pandemic…while Omicron does appear to be less severe compared to Delta, especially in those vaccinated, it does not mean it should be categorized as "mild", Tedros Adhanom said.

He added that the Omicron variant is hospitalizing people and it is killing people, just like previous ones.

"The tsunami of cases is so huge and quick, that it is overwhelming health systems around the world. Hospitals are becoming overcrowded and understaffed, which further results in preventable deaths from not only COVID-19 but other diseases and injuries where patients cannot receive timely care," the WHO chief also said.

Raising concern over the vaccine inequity and health inequity, WHO director-general Tedros said that these were the "biggest failures of last year."

"While some countries have had enough personal protective equipment, tests and vaccines to stockpile throughout this pandemic, many countries do not have enough to meet basic baseline needs or modest targets, which no rich country would have been satisfied with. Vaccine inequity is a killer of people and jobs and it undermines a global economic recovery," Tedros said.

Meanwhile, a new coronavirus variant B.1.640.2 also known as IHU variant has been detected in a traveller returning from Cameroon, according to the hospital IHU Mediterrannee in Marseille, France.

The traveller has reportedly infected 12 people in Southern France.