The World Health Organization on Tuesday warned against treating Covid-19 as an endemic infection and said that the virus is continuing to evolve.

The global health body also cited a research centre, Institute for Health Metrics and Evaluation, as saying that at the current rate of transmission, more than half of Europe may be infected with the Omicron variant in the next six to eight weeks.

Catherine Smallwood, the World Health Organization’s senior emergency officer for Europe, said at a virtual press conference that a disease is said to be endemic when it has a stable rate of transmission irrespective of external forces.

“[With Covid-19], we’re seeing an unpredictable level of transmission, and part of that is because the virus is continuing to evolve and Omicron being able to partially escape immunity,” Smallwood said. “We can’t just sit back and see a stable rate of transmission. It causes epidemics.”

Smallwood made the statement amid several political leaders downplaying the severity of the Omicron variant. In India, Uttar Pradesh Chief Minister Adityanath on January 3 compared the Omicron variant to a “common viral fever”.

A week later, Spanish Prime Minister Pedro Sanchez had claimed it may be time to track the pandemic differently as coronavirus’s lethality has fallen.

The World Health Organization’s Regional Director for Europe, Hans Kluge, on Tuesday said that the Omicron variant represents a new west to east tidal wave sweeping across Europe, on top of the Delta surge. He said that mortality rates are stable and are the highest in countries with high Covid-19 incidence and lower rates of vaccination.

Kluge said that Europe is now seeing rising Covid-19 hospitalisations because of the unprecedented scale of transmission. “It is challenging health systems and service delivery in many countries where Omicron has spread at speed, and threatens to overwhelm in many more,” Kluge added.

The official expressed concern that the Omicron variant may badly impact countries in the eastern part of the region, where vaccination levels are lower.

Hospitalisations in many parts of Europe are currently under strain amid sharply rising Covid-19 cases. Many hospitals in the United Kingdom have declared “critical incidents” because of rising pressure on account of Covid-19 and staff absences, the BBC reported.

France’s Health Minister Olivier Veran said last week that January may be a tough month for hospitals. According to him, Omicron patients were taking up a large number of beds in conventional wards, while Delta patients were leading to strain on intensive care units.