Countries Try Shorter Covid-19 Quarantines in Bid to Boost Compliance

Some disease and public health experts offer cautious support to the idea, saying that although data is patchy, such a trade-off might make sense, especially where citizens’ weariness or inability to comply with more burdensome restrictions are complicating efforts to beat back a resurgent pandemic. Cases in Europe are accelerating fast following a summer lull, and in the U.S. recently topped a new daily record of more than 80,000.

Others, though, including the World Health Organization, say it is a gamble that could backfire and will likely result in some additional cases slipping through. And gaps in knowledge about how exactly the virus behaves make it difficult to determine the best abbreviated cutoff date or strategy.

“There’s a trade-off because you might miss some people, but you could get so many more people to adhere to the quarantine requirements that the gains would far outweigh the people you might miss,” said Mark Plescia, chief medical officer for the Association of State and Territorial Health Officials, which represents state health departments in the U.S.

France in September cut to seven days from 14 the length of time those who have been in contact with a known case must quarantine at home. The country’s health authority concluded that citizens were reluctant to stay home for two weeks and said the risk of spreading the contagion lessens over time.

Belgium similarly shortened its quarantine period to seven days from 14 on Oct. 1, also citing weak compliance, but raised it to 10 days on Oct. 19 after a surge in cases. Spain in September cut its period of self-isolation after contact with a coronavirus carrier to 10 days from 14.

In Germany, public-health officials have said the quarantine period can be reduced to 10 days from 14 starting Nov. 8, though it is up to individual states to decide if they want to follow that recommendation. The U.K. government is weighing the case for a shorter quarantine but for now it remains at 14 days, Brandon Lewis, a member of U.K. Prime Minister Boris Johnson’s cabinet, said Sunday.

In the U.S., the Centers for Disease Control and Prevention is exploring ways to shorten quarantine periods for schoolchildren who have been in contact with infected people in an effort to speed their return to classrooms, though the two-week guidance hasn’t changed. The agency continues to recommend two weeks for adults as well.

Rules for incoming travelers are more varied. France, Belgium and Germany impose the same length of quarantine on travelers as residents are required to self-isolate, while Spain doesn’t impose any restrictions on international arrivals. Some countries, including South Africa, let arrivals forego quarantine if they can produce a negative test.

Japan requires all arrivals to quarantine for 14 days with exceptions for some countries. The U.K. applies a similar system.

The shifting regulations run counter to advice issued by the WHO and, in European countries, by the European Center for Disease Prevention and Control.

Some scientists and public-health officials say the extra risk might be worth it. The thinking goes that by reducing quarantine stays, more people are likely to see them through. That might have a bigger effect on suppressing transmission of the virus if longer spells of quarantine are routinely flouted, even after accounting for the risk that some people released sooner might be or soon become infectious.

Compliance is a worry for governments grappling with fraying public approval of their handling of the pandemic and growing impatience with compromises aimed at fighting the disease. A September study by researchers at King’s College London found only a quarter of adults surveyed in the U.K. who lived in a household where someone had Covid-19 symptoms had obeyed instructions to stay home.

Behind the guidance from the WHO and others are estimates of the incubation period of the virus, or the time from exposure to symptoms. That ranges from roughly two to 14 days. People tend to be infectious a few days before symptoms start, and some 40% don’t show symptoms but can still transmit the virus, making quarantine all the more critical for disease control, infectious disease experts say.

Several studies suggest the median time to onset of symptoms after exposure is around five days. One study, by epidemiologist Justin Lessler and colleagues at Johns Hopkins Bloomberg School of Public Health, found that 97.5% of those who develop symptoms do so within 11.5 days, according to a paper published in the Annals of Internal Medicine.

“Our upper bound of that 14 days still holds based on the data that we have seen,” Maria Van Kerkhove, Covid-19 technical lead at the WHO, said last month.

Some disease experts agree that it is better to stick with 14 days. “You want to minimize, as much as possible, the risk,” said Waafa El-Sadr, director of the Global Health Initiative at Columbia University’s Mailman School of Public Health.

For Dr. Lessler, there isn’t yet sufficient data to determine how effective any trade-off from shorter stays in quarantine would be in controlling infection. Some researchers are now trying to better understand the specifics of the relationship between when someone becomes infectious, develops symptoms and tests positive for the virus.

One middle way some public health authorities are exploring is testing for the virus midway through quarantine. Modeling focused on air travelers by researchers at the London School of Hygiene and Tropical Medicine suggested that testing after seven days was almost as effective as a 14-day quarantine in controlling transmission.

The state of Vermont maintains a 14-day quarantine period, but since June, close contacts of a coronavirus case have been able to get tested at the end of a week in quarantine. A negative result can bring it to an end for people without symptoms. But the opt-out doesn’t apply to residents or staff in settings such as nursing homes or prisons, where the risk is high.

“If we can increase compliance with quarantine but also make sure we have a quarantine policy that allows us to catch as many cases as we can, that’s the best of both worlds,” said Patsy Kelso, the state epidemiologist for infectious disease at the Vermont Department of Health.

Write to Jason Douglas at [email protected] and Brianna Abbott at [email protected]