The difference between quarantine, isolation, and social distancing, explained 

These are three public health tools to slow the spread of an outbreak.  

Coronavirus is spreading in the United States. How fast and far it will spread, how many people will get sick, and how many of those will die are still unknown.

This early phase of the outbreak is critical: We still have time to apply some of the lessons learned from China, where the virus originated and has taken the greatest toll so far. New cases in China are now declining thanks to the government’s dramatic measures to contain the virus — mainly case finding, contact tracing, and suspension of public gatherings — as World Health Organization epidemiologist Bruce Aylward, who led a recent mission there, told my colleague Julia Belluz.

Here in the US, public health officials have many of the same tools to slow the spread of the virus, and as the experience of China shows, using those tools can help.

As of March 2, there were 43 cases in 10 US states and growing, and six deaths, meaning you’re probably going to be hearing about some of them soon. In Washington state, virologists suspect the virus has been circulating for a few weeks. There, state officials are considering closing schools and are expanding testing for the illness.

As we explained last week, local city and state governments are largely in charge of combating outbreaks in their regions. The federal government can do things like mandate travel restrictions across borders, or quarantine travelers coming into the country. It advises the country on outbreaks via the Centers for Disease Control and Prevention, and aids local governments with resources, data, and money. It’s also critical in creating and approving diagnostic tests for the coronavirus — which let officials know where the virus is and how far it’s spreading (though the government has been slow in rolling out tests). But its authority beyond that is limited.

So what might your city and state do (with or without the support of the feds) if cases ramp up in your area?

These three public health tools could (possibly) slow the spread of the outbreak

Beyond the overarching personal message of good personal hygiene (wash your hands, don’t touch your face), there are several other broad public health strategies used to put the brakes on a viral outbreak.

Three of the most important — and sometimes confusing — ones are isolation of sick patients and tracing their contacts, quarantine, and social distancing. These phrases are often used interchangeably, but they refer to slightly different things:

• Isolation is separating those with confirmed infections from other people, so that they can get better without infecting anyone else.
• Quarantine is restricting the movement of, or isolating, people who might have been exposed to an infection but who aren’t yet sick.
• Social distancing refers to a slew of tactics meant to keep people from congregating in large crowds, to slow the spread of a virus.

All of these might be called for during an outbreak, to varying degrees of effectiveness, and result in varying degrees of hardship for individuals. Your state or local government may have the power to enforce adherence to any of these — perhaps even with law enforcement. But we shouldn’t think of these (if implemented properly) as punitive, but as a civic duty to protect the most vulnerable from Covid-19.

Here’s what you need to know about each tactic.

Isolating sick patients and tracing their contacts

If you can identify everyone who has been infected with the virus and safely isolate them from other humans while they are in treatment, you can stop outbreaks for which there are no vaccines or treatments.

Stopping an outbreak “really comes down to how good individual public health agencies are at detecting cases, getting them care, putting them into isolation, and how good the people who are infected are at their own hygiene,” Nathan Grubaugh, an epidemiologist at the Yale School of Public Health, said in January. (Isolation was the main way the 2003 SARS outbreak was contained.)

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Isolation of the sick may help slow the spread of the current Covid-19 outbreak. But experts doubt it can be totally contained and stopped in this manner. “There’s already too many undiagnosed cases out there,” Tara Smith, a professor of epidemiology at Kent State University, says. People with Covid-19 may be spreading the virus before they have symptoms, or they may have mild symptoms and are going about their daily lives spreading the virus.

A key to making isolation work is to pair it with contact tracing. While sick patients are in isolation, public health workers can do detective work, figuring out all the people those patients had contact with. That way, they can find a patient’s source of the disease and potentially isolate them, as well as identify people who are at risk of contracting the disease and place them under isolation or quarantine.

Quarantine

In a quarantine, people who may have been exposed to an infection are asked to remain at home, or in another place, isolated from other people. Quarantines can target just individuals who have traveled to affected countries, or could end up involving large groups of people (say, if a school’s entire student body may have been exposed to the infection).

State governments, as well as some large cities, have the power to order mass quarantines, or the practice of isolating people who may have been exposed to a virus in order to prevent them from spreading the illness before they start experiencing symptoms. These laws also generally apply to the isolation procedures mentioned above.

The power is not only to order quarantines or isolations, but also to enforce them. “Public health is actually a police power that is delegated to the states,” says Rebecca Katz, director of the Center for Global Health Science and Security at Georgetown. “You could end up with someone coming to your door and saying, ‘You’ve been exposed, and you’re either coming with me or you have to stay in your house.’”

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They could force you to stay at home or detain you in a facility. Katz says these detainment powers are rarely, if ever, used. To start, a quarantine order would probably be voluntary, and possibly limited to people who know for sure that they have had direct contact with an infected person. (Katz suggests that if it comes to it, think of quarantine as jury duty — an annoying civic duty you just have to endure.)

But the problem with many states’ quarantine laws is that they have not been updated in decades, or don’t provide clear protections for civil liberties or in the case of missed work.

Katz has researched the variety of quarantine laws that exist across states. “Most of these laws are really old and haven’t been updated,” she says. “A lot of the state-level regulations have not been updated since the civil rights and individual rights laws of the ’60s and ’70s went into effect.” Some laws don’t provide protections such as a right to legal counsel when being quarantined. Only 20 percent of states have provisions to keep people from being fired due to missing work during a quarantine.

The upshot: Because many states haven’t bothered to revise these laws, they haven’t thought through what a modern-day quarantine should look like or what rights need to be respected.

Katz’s co-authored 2018 paper on this sums it up starkly:

Fewer than half of state laws even include right to counsel during a quarantine, and many fewer have written protections for being able to choose a medical provider or receive compensation for damages that may occur. While half of the states have granted explicit police powers to enforce public health actions during a quarantine, half do not. And only 20% provide any employment protection for individuals forced to stay away from work for the betterment of society. More worrisome, less than half of the states have language in their laws and regulations related to providing safe and humane quarantines.

“We believe the variation between states and the inclusion of curious rules creates an environment across the country that will result in unease, confusion, and possibly civil unrest if large-scale quarantines are ever required,” the paper concluded.

As Maggie Koerth explains at FiveThirtyEight, the evidence on whether quarantines have worked to slow the spread of past outbreaks is mixed. It can be hard in an outbreak to identify those who qualify for quarantine (i.e., people who may have been exposed but who are not yet sick). Quarantines can sometimes result in more cases, like what happened on the Diamond Princess cruise ship. There, quarantine led to more people becoming infected.

And there are other downsides besides those mentioned above: People routinely break quarantine orders, Koerth reports, and restricted movement of people (and the goods and services they provide) can result in other hazards.

Social distancing

Isolation and quarantine depend on public health officials’ ability to speedily detect cases, or possible exposures, to an infection. But what if a dangerous virus is circulating broadly in a population? That’s where social distancing measures come in. Overall, these aim to keep human beings around six feet apart from one another.

“Unlike quarantine and isolation, social distancing orders typically apply to whole communities, not specific individuals,” Lindsay Wiley, a health law professor at the Washington College of Law, explains in an email.

These measures include postponing or canceling mass gatherings like sporting events, concerts, or religious gatherings. It could mean closing schools or encouraging telework. (Other good practices during any outbreak: Stay home if you’re sick, cover your coughs and sneezes, and wash your hands.)

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“A local health department may ask — or order — private businesses and organizations to cancel events where large crowds are expected to gather,” Wiley says. “Or, if it is determined that children play an important role in transmitting infection, state and local officials may order public and private schools and day cares to close. These decisions would be made primarily at the local level — city by city, county by county.”

Because these decisions are local, they can result in inconsistencies. One school district might be closed due to coronavirus fears, while another stays open. And these decisions are often influenced by political concerns.

Political responses to the outbreak may be wide-ranging. Some may fear that acting will hurt their local economy, while others may overreact. In 2014, during the Ebola outbreak, a teacher in Maine was placed on leave because he had traveled to Dallas, where an Ebola patient died in a hospital (the teacher had not visited the hospital). That same year, then-New Jersey Gov. Chris Christie forced a nurse who had treated Ebola patients in Africa into quarantine. She never exhibited symptoms of the disease, and experts concluded she posed no risk. But the governor held her in isolation anyway. The nurse ended up suing the state, arguing her rights had been infringed on.

We may not know what social distancing measures will come into place, but we can start preparing for them now.

“Think about what you’d do for child care if schools or day cares are closed,” the CDC’s Nancy Messonnier suggested during a recent press briefing. “Is teleworking an option for you? Does your health care provider offer a telemedicine option? All of these questions can help you be better prepared for what might happen.”

Further reading: Preparing for an outbreak

• Vox’s Kelsey Piper has a great, level-headed guide for how your household can prepare for an outbreak.
• And Julia Belluz has you covered if you’re thinking about travel during the outbreak.