Europe is now in the midst of a fourth wave of coronavirus.

In the past week alone, Austria, the Netherlands, Denmark, Germany, Finland, Norway and other northern European countries have recorded their highest case rates since the pandemic began. 

The sudden revival of cases to levels not seen since spring has led to a new wave of lockdowns across the Continent. 

Austria has become the first country to reintroduce a full lockdown after average daily cases hit 153 per 100,000 people on Monday, far eclipsing its previous peak recorded almost exactly a year ago. 

Meanwhile France is set to tighten enforcement of its Covid health and strengthen social distancing rules, while ministers in the Netherlands prepare to announce new restrictions on Friday in an attempt to alleviate pressures on hospitals.

Slovakia is already heading back into full lockdown amid record high case rates. 

In all, the University of Oxford’s Stringency Index, a project aimed at measuring the toughness of rules in nations across the world, suggests that almost a third of countries in Europe have toughened their rules in the past month. 

The intensity of the fourth wave cannot be understated. As of Sunday Nov 21, one in four European countries has seen its highest case rates since the start of the pandemic. 

A mixture of increased mobility as countries were weaned off restrictions and a sharp drop in temperatures across the Continent has meant people are spending more time together indoors. 

There are some indications that southern Europe is at the beginning of a winter uptick as well, but generally rates in Italy, Spain and Portugal remain at lower levels. 

Some countries in Eastern Europe, including Latvia, Lithuania and Bulgaria, are already seeing substantial declines in case rates. 

Their fourth wave began almost a month before their western neighbours, forcing some of the strongest measures in Europe. Latvia, for example, implemented mandatory vaccinations for all employees. 

This early, heavy fourth wave in eastern and central Europe was most likely aided by comparatively low vaccine uptake in the region. 

On average, just 39 per cent of people in Eastern European countries have received two doses, compared with around 62 per cent in South Europe and 67 per cent in Western Europe.

However, some European countries may be the victims of their own early success in rolling out the vaccine earlier in the year, with immunity to the virus waning around five months after the second dose. 

This has led to an acceleration of booster programmes in Austria, Germany and France. 

Despite waning immunity, the ability of the vaccine to prevent serious cases and potential hospitalisation is clear in the data. 

Where Austria has surpassed its peak Covid rates, the proportion of people in hospital is still under half that seen in January and there are signs of admission rates slowing down as its booster program kicks in. Similar trends are being seen in the Netherlands. 

Contrast that with comparatively poorly vaccinated Bulgaria, where cases peaked but with little vaccine-driven immunity, hospital cases were able to hit as high 80 per cent of their peak. 

The UK has seen high, but stable, case rates since restrictions were lifted in July – leading to a “sick man of Europe” status over the summer. 

There are hopes that this high level of natural immunity mixed with a high proportion of booster uptake among vulnerable, older adults will allow for a stable winter in Covid cases. 

But this has come at a cost; the UK has seen 15,000 deaths from Covid over the period, double that of Germany and France. 

Whether this gap exists at the end of the winter will be determined by how long restrictions are in place and whether immunity can be boosted quickly enough.