France delayed the planned lifting of coronavirus restrictions in a key region on Wednesday as its chief scientific advisor warned the delta variant could cause a fourth wave of infections.

Europe is now in a race to vaccinate enough people to avoid another damaging wave of Covid-19 like that currently gripping the UK.

“We do not want to take the risk of having a re-start of the epidemic,” said Gabriel Attal, a French government spokesman, as he announced the national easing of restrictions would be delayed in the Landes region until at least July 6.

The region has experienced a particularly high number of cases of the delta variant, which was first identified in India and is behind the current wave in the UK.

“We have all the cards in hand to avoid a fourth wave of the epidemic,” said Mr Attal.

But Professor Jean-François Delfraissy, the French government’s chief scientific advisor, said a fourth wave was likely in September or October.

“I think we will have a fourth wave, but it will be much more moderate than the previous three waves because the level of vaccinations is different compared to before,” he said.

Cases, deaths and vaccinations, coronavirus world map

Jens Spahn, the German health minister, has urged caution over the delta variant despite the country’s sharply falling infection numbers.

The variant now accounts for 15 per cent of all infections in Germany and its share is doubling by the week.

Concern in Germany has focused on the risk of more cases of the variant being imported by travellers returning from summer holidays.

Several regional governments this week demanded tougher restrictions on those returning from amber list destinations. Germany has an extra “low risk” subcategory where people can end self-isolation at any time with a negative test.

Leading German politicians have been critical of the large crowds allowed at Euros football matches in the UK, and one, Karl Lauterbach, described the championships as a “firestarter for the delta variant”.

Mario Draghi, the Italian prime minister, last week questioned whether the Euro 2020 final should be held at Wembley given the number of delta cases in the UK.

The Italian national health institute said the delta variant is likely to become dominant as it has in the UK.

Daily Covid-19 tests vs daily confirmed cases in Europe

“Our epidemiological monitoring shows a rapidly evolving picture that confirms that also in our country, as in the rest of Europe, the delta variant of the virus is becoming dominant,” said Anna Teresa Palamara, the director of the Infectious Diseases Department of ISS, the national health institute.

The European Centre for Disease Prevention and Control said last week that it expected the delta variant to represent 90 per cent of all cases in the EU by the end of August.

The variant is starting to gain ground in Spain too, but health ministry officials are playing down its impact and do not believe that it is behind an uptick in cases over the past few days.

The most recent nationwide figures showed that the delta variant was reaching 15 per cent in some areas of Spain, but these results are from early June, and the variant’s incidence is already thought to be far higher.

Monday and Tuesday have seen rises in Spain’s 14-day cumulative caseload over 100 per 100,000 inhabitants, with a notably higher level of more than 250 among people in their twenties as school years end and the impact of increased travel and socialising kicks in.

“The delta variant may occupy more space but this uptick in cases is not associated with it – maybe in localised cases, but not nationally,” said Fernando Simon, director of Spain’s health emergency centre.

“It is in the groups who haven’t been vaccinated that we are seeing a real rise in transmission. All vaccinated groups are maintaining the downward trend.”

Russia, South Africa and Indonesia have been hard hit by delta

In Belgium too the variant is mainly spreading through young people less likely to be fully vaccinated, experts have warned.

The variant accounted for about 15.7 per cent of cases in Belgium last week, and it is predicted to reach 80 to 90 per cent by the end of July.

In the Netherlands, the health ministry warned increased testing is vital to stem the spread of the delta variant. Everyone who returns from a holiday in a risky area needs to be tested on their return, said a spokesman.

The number of people reporting for tests has been dropping for months and the ministry is considering handing out tests at Amsterdam’s Schiphol Airport.

Poland said it may see a fourth wave as soon as mid-August. At the moment the country is reporting around 100 cases a day, far fewer than the 30,000 high around the end of March.

“On the one hand, I’m glad we have fewer infections, but on the other hand I’m worried,” Waldemar Kraska, Poland’s deputy health minister, told the Polish Press Agency (PAP). “I’m worried because people believe there is no pandemic and no need to be careful.”