LONDON – Europe is lagging behind in its vaccination campaign and could see hundreds of thousands more deaths by next spring, the World Health Organization said.

“We have fully vaccinated only 54% of the 1 billion people living in Europe,” Robb Butler, executive director of WHO Europe, told CNBC on Wednesday.

This region for the UN health agency includes 53 countries that actually stretch across Europe and Central Asia and, at their last census, had about 900,000 inhabitants.

“There is [around] 45% who are unvaccinated or not fully vaccinated is currently a bigger issue for our policymakers and decision-makers – to increase vaccination rates, ”he told CNBC’s Squawk Box Europe on Wednesday.

Butler’s comments come as Europe grapples with the latest wave of Covid infections, which has led to further restrictive measures and increased hospital admissions.

Most, if not all, of the people admitted to hospital intensive care units with Covid are unvaccinated, health officials across the region reported. Covid vaccines can’t completely stop the transmission of the virus, but they do significantly reduce the risk of serious infections, hospitalizations, and death.

The large proportion of unvaccinated people in Europe is at risk of excessive deaths in the coming months, the WHO warned Tuesday, issuing a statement saying the Covid death toll could rise by 700,000 in Europe and Central Asia to increase reach than 2.2 million by next March.

The Europe region has already recorded 1.5 million Covid deaths, with the virus now becoming the leading cause of death in both Europe and Central Asia, the WHO European branch said.

The region currently has nearly 4,200 deaths per day, double the daily deaths recorded in late September, the statement said.

The WHO has repeatedly stated that Europe is at the epicenter of the latest global wave of Covid infections. The vaccination rates, both for the first Covid vaccination programs and for the booster vaccinations, differ greatly from country to country.

Germany is considering tighter Covid restrictions that could include lockdown measures, with a decision expected on Wednesday. Meanwhile, Spain is tightening controls as the number of infections increases. Austria has opted for a complete block and the Netherlands for a partial block.

Austria is so far the only country in Europe that will make Covid vaccines compulsory from February next year, although there have been calls for mandatory vaccination in other countries.

WHO’s Butler said the health agency had no position on mandates but said they were “a very sensitive” issue.

“It polarizes, you risk marginalizing it [people] and it can come at the expense of trust and social inclusion. So it is a very delicate measure, a final measure. The lessons of history have shown us that where vaccines are mandated or mandated, confidence eroded and we saw that polarization, ”he said.

The President of the European Commission, Ursula von der Leyen, on Tuesday called for the use of booster vaccinations and said other preventive measures needed to be taken to keep the number of infections low.

“Further measures are necessary to prevent or slow down the spread of the virus. So social distancing, wearing masks and hygiene rules. All of this remains equally important. I know that it is really very difficult for many of us, but we mustn’t forget anything. In the EU, 1,600 people die of Covid every day, 1,600 people every day, “she noted.

“Therefore, vaccination and hygiene measures are an act of solidarity and save lives,” she added.

– CNBC’s Robert Towey contributed to this story.