The World Health Organization chief warned on Tuesday that the pandemic is "nowhere near over", adding that new variants are likely to continue emerging after Omicron.
"This pandemic is nowhere near over and with the incredible growth of Omicron globally, new variants are likely to emerge, which is why tracking and assessment remain critical," said Dr Tedros Adhanom Ghebreyesus, director-general of the World Health Organization, at a press conference.
The new, highly transmissible Omicron variant was first identified at the end of last year and has swept across the globe fuelling record-high cases in Europe and globally. WHO officials said that while the variant is less severe on average, it is still causing hospitalisation and death.
"Speaking purely of this as a mild virus or less severe gives an impression that this would be less severe in its impact on the health system. That is not the case if the virus is able to spread uncontrollably throughout society and that's why we have advised continued adherence to measures," said Mike Ryan, the WHO health emergencies programme executive-director.
The warnings come as some governments suggest they may treat COVID-19 as an endemic illness, one that is regularly found among people such as a cold or flu virus.
Maria Van Kerkhove, the WHO's COVID-19 technical lead, said that the virus is "circulating at a very intense level around the world" and urged countries not to abandon public health measures such as distancing and masking.
"This won't be the last variant of concern," she said.
The variant has currently had the highest level of immune escape, causing more infections among people who are vaccinated, officials said.
"Against Omicron, many of the vaccines have shown a reduction in efficacy against infection and that's why we see a lot of breakthrough infections (cases in vaccinated individuals) but these are mostly not resulting in severe disease, so that's a positive," said Soumya Swaminathan, the World Health Organization's chief scientist, adding however that there's a slight drop in protection against severe disease as well over time.
She said the agency was still looking into how countries should think about giving booster shots to their populations. She added that the focus is to vaccinate and provide primary doses to those who are not yet vaccinated.