"Last week the number of cases rose by 10 per cent driven by increased mixing, travel gatherings and easing of social restrictions," WHO Regional Director for Europe Hans Kluge said.
Europe will have mostly Delta variant COVID-19 infections but not be fully vaccinated by August, warned the World Health Organisation (WHO) on Thursday.
The Delta variant, which is more transmissible than other COVID-19 variants, is already behind a rise in infections in the UK despite high vaccination rates there.
Dr Hans Kluge, the WHO Regional Director for Europe, said that COVID-19 cases were now rising for the first time in 10 weeks in the European region which includes some Central Asian countries.
"Last week the number of cases rose by 10 per cent driven by increased mixing, travel, gatherings and easing of social restrictions," Kluge said at a press conference on Thursday, adding that the Delta variant is already overtaking other variants in the region.
"By August, the WHO European region will be Delta dominant but by August, the region will not be fully vaccinated. 63 per cent of people are still waiting for their first jab," Kluge said.
While the vaccine is effective against the Delta variant, it is only effective after two doses so authorities are encouraging people to get a second vaccine dose.
New virus wave is possible before autumn
Kluge warned that there would be a new virus wave in the region unless people were disciplined and vaccinations increased.
"The three conditions for a new wave of excess hospitalisations and deaths before the autumn are therefore in place: new variants, deficit in vaccine uptake, increase in social mixing," Kluge said on Thursday.
Kluge added that the situation looked similar to where we were last year where transmission and greater social mixing led to large virus waves in the autumn and winter lockdowns.
"The window of opportunity to act is now," he said, explaining that as long as the virus was circulating, there would be more variants.
Dr Catherine Smallwood from WHO's health emergencies programme added that the virus surge could come earlier than the autumn.
"If we have large groups of populations that have not had two doses of COVID-19 vaccine, the increase in cases that we're already seeing in several countries across the region will be resulting and will coincide with increasing hospitalisations and increasing deaths," she said.
"So the concern as we've been saying for months now of an autumn resurgence is still there but what we're seeing now is that it might even come before the autumn."