Germany has privately declared they're in the throes of a "third wave" of Covid-19, amid fears several other European countries are headed down the same path.
As the vaccine rollout begins, health authorities in the Netherlands, Sweden, Ukraine and Greece have also reported spikes in new coronavirus infections.
Late last year, the World Health Organisation's (WHO) special Covid-19 envoy warned of such an event, predicting Europe could face a third wave of the pandemic if governments repeated the mistakes that had led to the second.
"(Governments) missed building up the necessary infrastructure during the summer months, after they brought the first wave under the control," the WHO's David Nabarro said in an interview with Swiss newspaper Solothurner Zeitung.
"Now we have the second wave. If they don't build the necessary infrastructure, we'll have a third wave early next year."
German Chancellor Angela Merkel all but confirmed their prediction on Tuesday, informing MPs in her conservative party that "we are now in a third wave", two sources who were at the meeting told Reuters.
Merkel reportedly warned that any easing of lockdown measures – introduced late last year and set to end on March 7 – would have to be done at a gradual pace.
It comes just days after the nation's Health Minister, Jens Spahn, urged caution in the face of rising case numbers.
The prospect of a virus resurgence isn't isolated to Germany alone. Confirmed virus infections in the Netherlands rose by nearly 19 per cent over the past seven days, with the National Institute for Public Health declaring the nation was also experiencing a "third wave".
"Because the majority of the population has not yet been vaccinated, it is very important to prevent infections as much as possible and to keep this third wave as low as possible," the institute said.
"This is only possible if a relaxation (of the lockdown) is done with great caution and step-by-step."
Meanwhile, Stockholm has seen a 27 per cent rise in case numbers in recent weeks, with authorities urging people to use face masks when catching public transport and while at shops and in the workplace.
"We want people to use face masks in public transport around the clock, especially during rush hour," the city's infection control doctor, Maria Rotzen Oslund, said.
Sweden's chief epidemiologist, Anders Tegnell, attributed the surge in cases to the UK variant, saying the "mutant" strain "has increased at a very fast pace" and the nation "unfortunately is seeing an upswing again".
Greek health authorities also noted a spike in new cases, while in the Czech Republic officials have warned the country's health system was on the brink of "absolute exhaustion" and may need help from abroad.
In the last fortnight, the nation has recorded close to 1000 new cases of Covid-19 per 100,000 people – the EU's highest infection rate in per-capita terms.
On Tuesday local time, Deputy Health Minister Vladimir Cerny told reporters if the trend continued, hospital capacity would be overwhelmed in less than a month and other nations could be sought to take in patients.
"We are starting to talk about help from abroad. So far, the only official offer came from Germany, which offered a place for nine patients," he said.
"The current free capacity of hospitals in the Czech Republic is about 15 per cent."
The situation in Slovakia is equally as dire. A one-day screening exercise earlier this month showed the UK strain was responsible for 74 per cent of new cases, while the country has had the highest number of Covid-19 deaths per capita in the world over the past week.
Other countries in the EU have been asked by Foreign Minister Ivan Korcok to send additional vaccines, with hopes it might help them cope with the "tragic" situation.
"I fully realise that other countries have a vaccine shortage as well but Slovakia now, also based on the fact that we have the highest death rate, at the moment needs it most," he told reporters in Brussels.