France’s prime minister made the announcement in a televised speech yesterday, along with several other new measures to combat the spread of coronavirus.
The new seven-day quarantine, which replaces the previous 14-day rule, covers anyone who tests positive for the virus and anyone who has been in close contact with someone who tests positive for the virus.
Prime Minister Jean Castex said during the speech: “The virus is circulating more and more in France. Even if it is circulating mostly among the young...it ends up infecting the most vulnerable.
"We are seeing a significant increase in the number of people hospitalised," he said.
Why reduce the quarantine to seven days?
Health minister Olivier Véran told France Inter on Tuesday that we are “more contagious in the first five days following the appearance of symptoms or testing positive. After, this contagiousness decreases in a very significant way,” he said.
“Beyond a week, the contagiousness remains but it is very weak,” he said, adding that this is the reason the government was considering reducing the quarantine period.
Benjamin Davido, an infectologist at Raymond-Poincaré hospital in Paris, told France 2 that "most of the contamination occurs in the first five days".
What do the experts say?
Antoine Flahault, professor of public health and director of the Institute of Global Health at the University of Geneva, supported reducing the quarantine period, specifically for non-symptomatic carriers of the virus.
“We must now be pragmatic and efficient: quarantines must now become five-day weeks. Beyond five days, less than 10% of carriers of non-symptomatic viruses are contagious,” he tweeted.
Professor Flahault told French weekly paper le Journal du Dimanche earlier this month that for the isolation period, “the shorter it is, the easier it is to observe, the more effective it is.”
“We cannot claim there is zero risk, but the measures would be better accepted socially,” he added.
William Dab, former directeur général de la santé, disagreed.
“Seven days, it is not wise,” he told le Journal du Dimanche. He said he feared a reduction to the period of isolation would lower people’s guard “at the moment when the circulation of the virus has once again become very active.”
Yesterday, Mr Castex announced that France would be increasing the number of departments in the red zone from 28 to 42.
This denotes areas where the virus is actively circulating, and gives prefects in those departments the power to introduce new measures to combat the spread of coronavirus.
Dr Jean-Paul Hamon, president of the Fédération des Médecins de France, said that "testing capacities are currently not adapted to this seven-day period", with results sometimes only being available after "three, four or even five days".
Around France there have been reports of people facing long delays to get tested for coronavirus and to receive test results.
Epidemiologist Martin Blanchier thinks reducing the quarantine is more a question of practicality.
“You have to imagine that today we have a million tests. Two thirds are people who think they are contact cases and of those there are 3% positive cases," he told radio station RMC.
“So if every time we think we've been in contact [with someone with Covid-19] we quarantine ourselves, we end up with 90% of the quarantines being useless.”
Opinions outside of France
There has also been talk of reducing the length of quarantine outside of France.
Christian Drosten, who directs the Institute of Virology at the Charité Hospital in Berlin, told German public broadcaster NDR that he supported the idea of a five-day quarantine.
“It's no use having all kinds of school classes, all kinds of workplaces, under weeks-long quarantine,” he said.
Germany has declared that from October, people returning from high-risk regions abroad will only have to quarantine for five days.
However, the EU has cautioned countries looking to reduce their quarantine periods.
“We are looking to provide some evidence to decision makers on what kind of risks they would take if quarantine was shorter,” Andrea Ammon, head of the European Centre for Disease Prevention and Control (ECDC), told EU lawmakers in a hearing in early September.
She said that in 3 - 4% of cases, infections emerge only after two weeks, news agency Reuters reported.