Dr. Tedros Adhanom Ghebreyesus, the head of the World Health Organization, said Thursday that while the COVID-19 omicron variant seems to be less severe than delta, it should not be categorized as mild.

"Just like previous variants, omicron is hospitalizing people and it is killing people," he said. "In fact, the tsunami of cases is so huge and quick, that it is overwhelming health systems around the world."

World Health Organization Director-General Tedros Adhanom Ghebreyesus gives a press conference on December 20, 2021 at the WHO headquarters in Geneva.(Photo by FABRICE COFFRINI/AFP via Getty Images) (FABRICE COFFRINI/AFP via Getty Images)

Mangala Narasimhan, the director of critical-care services at Northwell Health in New York, told the Wall Street Journal that only about 10% of patients are ending up in the ICU due to illness compared to up to 35% in previous surges. She told the paper that individuals who are vaccinated are—on average—hospitalized for four days while those who are unvaccinated stay for almost two weeks.


A health worker inoculates a boy with the CoronaVac vaccine, developed by China's Sinovac against the novel coronavirus disease COVID-19, at a vaccination centre in Bogota. (Photo by Leonardo MUNOZ / AFP) (Photo by LEONARDO MUNOZ/AFP via Getty Images) (LEONARDO MUNOZ/AFP via Getty Images)

The WHO emergencies chief, Dr. Michael Ryan, said speculation that omicron might be the last variant of the outbreak was "wishful thinking" and cautioned: "There still is a lot of energy in this virus." 


Added Maria Van Kerkhove, WHO’s technical lead on COVID-19: "I think it’s very unlikely that omicron will be the last variant that you will hear us discussing." 

The Associated Press contributed to this report