The World Health Organization’s Europe office says projections show its 53-country region could face another 700,000 deaths in the coronavirus pandemic by next spring, topping 2 million in total.

WHO Europe, which is based in Copenhagen, Denmark, also cited growing evidence of a decline in protection against infection and mild disease through vaccines, and said a “booster dose” should be given as a priority to the most vulnerable populations — including people with weakened immune systems — as well as people over age 60 and health care workers.

The U.N. health agency’s international headquarters in Geneva, however, has repeatedly called for a moratorium on the use of boosters through year-end so that doses can be made available for many developing countries that have faced a severe lack of the COVID-19 vaccines compared to the rich world.

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WHO Europe called on people to get vaccinated and respect proper hygiene and practice social distancing to help stop the spread of the virus.

“Today, the COVID-19 situation across Europe and Central Asia is very serious. We face a challenging winter ahead, but we should not be without hope, because all of us — governments, health authorities, individuals — can take decisive action to stabilize the pandemic,” said Dr. Kluge, the regional director for WHO Europe, in a statement.

The European region, which stretches deep into central Asia, reported that deaths due to COVID-19 rose to nearly 4,200 per day last week — a doubling of levels recorded at the end of September. Cumulative deaths have now reached 1.5 million in the region.

The three factors driving the increase are the highly transmissible delta variant of the virus, an easing of restrictive measures like requirements for mask-wearing and physical distancing in places, and large swaths of the European population that remain unvaccinated, WHO Europe said.

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“We can expect that there will be high or extreme stress on hospital beds in 25 countries, and high or extreme stress in intensive care units (ICUs) in 49 out of 53 countries between now and 1 March 2022,” a WHO Europe statement said. “Cumulative reported deaths are projected to reach over 2.2 million by spring next year, based on current trends.”

It said the region could face a cumulative 2 million deaths due to the pandemic by March 1.