Europe is divided as it enters another Covid-19 winter. In some countries, people are dying from the virus at record rates. Elsewhere, infections are rising—but from low levels that policy makers say are the result of a suite of restrictive policies.

Winter is the time of greatest peril in the fight against Covid-19 as people move indoors, often into poorly ventilated spaces, helping the virus to spread. Health systems are also often strained by other seasonal ailments, such as flu.

In Italy, Spain and much of the rest of Southern Europe and France, deaths, hospitalizations and confirmed infections from the virus are rising, but still relatively subdued.

Many policy makers and public health experts attribute this to high vaccination rates, the use of masks indoors and policies that nudge, and in some cases, push people to get vaccinated. Restrictive measures are making a comeback in other countries, including Denmark, Austria and the Netherlands.

“Right now things are under control, but there is fear that there could be a new wave,” said Arrigo Paciello, the director of pharmacology for the national health system in Bergamo, one of Italy’s hardest-hit cities during the pandemic.

Yet in much of central and Eastern Europe, vaccination rates are relatively low, opening the way for the highly infectious Delta variant of the coronavirus to spread freely. In Bulgaria and Romania, the pandemic is raging with Covid-19 deaths and confirmed infections at, or near, record highs.

Hundreds of people have been dying daily in Romania, a country of 19 million people where the healthcare system is overwhelmed and some patients have had to be transported to neighboring countries. Next-door Bulgaria is struggling with a similar crisis, with deaths and hospitalizations spiraling.

Meanwhile, Germany on Tuesday notched a record of confirmed infections, which are now averaging about 30,000 a day, compared with less than 1,000 in July and a peak of about 25,000 last winter. Deaths, though rising and much higher per capita than in Italy and Spain, are well below previous peaks.

In the U.K. where there are almost no Covid-19 containment restrictions, daily confirmed infections are trending down, but are still about four times higher than in France, which has a similar population and vaccination rate. The U.K. is averaging almost 170 Covid-19 deaths a day, compared with fewer than 40 in France.

On Tuesday, French President Emmanuel Macron noted case rates had risen 40% in a week and—in a move to encourage the take-up of booster shots—said people 65 years and over would be required from Dec. 15 to show proof of a booster shot to gain access to restaurants and some public spaces.

Even in places with still relatively low daily confirmed infections, public-health officials are on high alert because most consider it inevitable that there will be a steep climb in confirmed infections as temperatures drop and more of daily life moves indoors.