Europe could soon enter a “long period of tranquillity” that amounts to a “ceasefire” in the pandemic thanks to the less severe Omicron variant, high levels of immunity and the arrival of warmer spring weather, the World Health Organization has said.

In an upbeat assessment, Hans Kluge, the WHO’s Europe director, said the region was in a position of “higher protection” that could “bring us enduring peace”, even if a new, more virulent variant than Omicron should emerge.

Kluge said the 53-country region – which includes the UK – had recorded 12 million new coronavirus cases last week, the highest single weekly total of the pandemic, with about 22% of all tests returning a positive result.

However, hospital admissions, although growing, were not rising at the same rate and the number of patients in intensive care was not increasing significantly, he said. The number of deaths across the region was also starting to plateau.

Kluge said “a large capital of vaccine-derived and natural immunity, a favourable seasonality pause and a lower severity of the Omicron variant” meant governments now had “a singular opportunity to take control of transmission”.

This opened up the prospect of “a long period of tranquillity and a much higher level of population defence” against any fresh resurgence in infection rates, he said.

The optimistic forecast comes days after Kluge said it was “plausible” the region was “moving towards a kind of pandemic endgame”.

But Kluge stressed on Thursday that authorities must use the respite constructively, by continuing vaccine and booster campaigns, protecting the most vulnerable, promoting individual responsibility and intensifying surveillance to detect new variants.

“I believe it is possible to respond to new variants that will inevitably emerge without reinstalling the kind of disruptive measures we needed before,” he said. But he added it must now be a top priority to ensure all countries are equally well protected.

“This demands a drastic and uncompromising increase in vaccine-sharing across borders,” Kluge said. “We cannot accept vaccine inequity for one more day – vaccines must be for everyone, in the remotest corner of our vast region and beyond.”

On the eve of World Cancer Day, the WHO regional director also noted the “catastrophic impact” the pandemic had had on people with cancer as health systems struggled with screening, diagnosis and treatment during the past two years.

During the early stages of the pandemic, he said, diagnosis of invasive tumours fell by 44% in Belgium, colorectal screenings decreased by 46% in Italy, and in Spain the number of cancers diagnosed in 2020 was 34% lower than expected.

The situation in many countries had improved since then, he said, but “the knock-on effect of this disruption will be felt for years” and any respite from the pandemic must be used immediately to reduce backlogs for chronic care services.