PARIS — France is facing a worrying surge of the coronavirus crisis, the government said on Friday, warning that the number of new cases was rapidly increasing and that hospitals were seeing an uptick in admissions.
Many residents expected new restrictions, especially after the government’s scientific council said earlier this week that authorities would have to take “difficult measures.”
But the authorities did not announce new rules, vowing instead to improve the country’s vast testing program — which has been plagued by delays in recent weeks — and urging the French to continue social distancing measures.
The number of new cases has soared recently in France, where nearly 31,000 people have died of the coronavirus so far. The country registered about 54,000 new cases over the past seven days — less than Spain, but far more than other neighboring countries like Italy or Germany.
On Thursday alone, there were nearly 10,000 new confirmed cases, a record since the beginning of the pandemic. The surge in new cases is partly attributed to widespread testing, but the positivity rate for those tests has also increased — it was 5.4 percent this week, up from 1.5 in late July — meaning that the virus is also picking up speed.
Jean Castex, the French prime minister, said in a televised address on Friday that the authorities were particularly worried about a renewed increase in the number of hospitalizations, especially of elderly people.
“This shows there is no Maginot line,” said Mr. Castex, who was speaking after a special cabinet meeting to discuss France’s coronavirus response, referring to national fortifications built in the 1930s. Even if the virus is still mostly spreading among younger people, he said, it “inevitably” ends up reaching more vulnerable segments of the population.
Younger people are less likely to develop severe forms of Covid-19, the disease caused by the virus, which has limited the impact of the surge in cases on France’s health system so far.
But last week, the increase in the number of cases was highest among those 75 years and older, who saw a 44 percent jump compared with the previous week, according to the national public health authority, which noted in a recent report that young adults were “less systematic” in respecting social distancing.
In his address, Mr. Castex called for renewed discipline. “For several more months, we must demonstrate responsibility at all times,” he said.
But Mr. Castex ruled out another nationwide lockdown and said the government was trusting local authorities to act on a case-by-case basis. The mayor in Nice, for instance, decided this week to ban all visits to retirement and nursing homes.
Forty-two of France’s 100 departments are now classified red, Mr. Castex said, meaning that the authorities in each area can restrict public gatherings or limit business hours as they see fit.
Mr. Castex cited three areas — the cities of Bordeaux and Marseille, and the overseas territory of Guadeloupe — where the surge in cases and increased hospitalizations were especially worrying.
Over 5,000 patients are currently hospitalized in France for Covid-19, with about 600 of them in intensive care. That is still far fewer than at the peak of the outbreak in April, when over 32,000 people were hospitalized because of the coronavirus. But over the past week, about 300 new Covid-19 patients were admitted every day — about double the average number this summer.
The authorities are keen to stress — and experts readily acknowledge — that France is better prepared than it was this spring, when the first virus wave hit. But complacency is dangerous, they warn.
“We have tests and masks,” said Dominique Costagliola, an epidemiologist at the Pierre Louis Institute of Epidemiology and Public Health in Paris. “But as long as deaths don’t increase and intensive care units aren’t congested, many people think that calling the situation serious is overreacting.”
If the authorities wait until that happens, Ms. Costagliola said, “it will be too late to act.”
Compared with the spring, when the authorities implemented a strict nationwide lockdown, France has greatly ramped up its testing capacity, with over one million tests every week on average, up from 500,000 in August. Tests are free, regardless of symptoms or potential contacts, and do not require a medical prescription.
But laboratories are struggling to keep up. In Paris, it sometimes takes up to a week to get results back — although Olivier Véran, the health minister, has said that in 80 percent of cases results were available within 36 hours.
Lionel Barrand, president of the Union of Young Medical Biologists, said his laboratory near Strasbourg, in eastern France, had experienced such a surge that he didn’t have enough machines, reagents and employees to quickly process test results.
“The strategy is bad because it is not focused enough,” Mr. Barrand said. “It’s better to conduct 500,000 well-targeted tests with quick results than 1 million tests with an eight-day delay.”
Mr. Castex acknowledged on Friday that while the increase in testing was “excellent news” it had sometimes led to “overly long waiting times,” and he said laboratories would now set aside specific time slots for symptomatic patients or their close contacts.
He also said that the government would hire 2,000 contact tracers and that isolation for people who tested positive would be more strictly enforced, although he did not provide details. Mr. Castex also announced that the isolation period would be reduced to seven days from 14, in line with recent studies that showed risks of contamination dropped sharply after the eighth day of infection.
Jean-François Delfraissy, an immunologist who heads the government’s scientific council, said that France has to strike a delicate balance to “live with the virus.”
“During the summer we all needed to blow off some steam,” Mr. Delfraissy told Europe 1 radio on Friday. Now, he said, “we need to pull ourselves back together a bit.”
Constant Méheut contributed reporting.