Quarantine. Self-Isolation. Lockdown. Shelter in Place. What’s the Difference?

A glossary of terms in the coronavirus age.

Quarantine. Self-Isolation. Lockdown. Shelter in Place. What’s the Difference?

Public spaces have been deserted due to shelter-in-place orders.

Photo by Dan Jardine / Shutterstock

Since the novel coronavirus or COVID-19 first emerged in Wuhan, China at the end of last year, many of us have started to learn a new language of pandemics. Phrases like “distance learning” and “flattening the curve” have quickly entered our daily conversations.

One area where the terminology around COVID-19 can be confusing is in the different measures being adopted to contain its spread. These terms and exactly how they are used can vary from place to place and they are also evolving, but here we explain some of the most common ones.


In some other contexts there are important differences between a lockdown and a shelter-in-place order, though the basic idea is similar—they are orders to stay inside a certain building. A lockdown, however, is used to describe one in response to something like an active shooter, while shelter-in-place is usually in response to natural or environmental threats, like a tornado or a chemical spill.

It’s a distinction that’s blurred in the context of COVID-19, where the two terms are often used interchangeably and the shelter-in-place measures adopted in California, France, Italy, and elsewhere are frequently described as lockdowns.

Shelter-in-Place Order

Before it was adapted for the context of COVID-19, the term “shelter in place” was typically used in situations when authorities asked the public to seek protection from storms or other threats by remaining in their homes. These are legal orders often with the potential for fines or imprisonment if violated and not merely strong suggestions from public health agencies (as is the case with the regional agreement reached by Connecticut, New Jersey, and New York on March 15 and which Pennsylvania joined on March 19).

In the United States to date, only two states have adopted such measures. California announced a shelter-in-place rule, in the form of an executive order issued by Governor Newsom on March 19. New York’s Governor Cuomo announced a similar though slightly more relaxed order that will go into effect on Sunday, March 22. In both states, residents are now required to stay home with only limited exceptions—for example, traveling to get medical care or buy food.

Stay-at-Home, or Safer-at-Home, Order

The more benign-sounding “stay at home” has been used by some public health agencies when discussing what are effectively “shelter in place” orders. The state of California opted to use “Safer at Home” to describe its statewide order of March 19.

Essential Services

In many areas that have experienced sizable outbreaks of the virus, all non-essential services have been ordered to close temporarily. That raises the question of what qualifies as essential. Even the most restrictive measures typically exclude banks, gas stations, pharmacies, and grocery stores from mandatory closures.

Beyond that, what is essential varies between jurisdictions. In California, for example, essential services also include convenience stores, laundromats, and take-out restaurants. In Europe, as the Washington Post reported, wine stores are considered essential in France while newsstands remain open in Italy.

Nonessential Travel

Many State Department warnings advise against nonessential travel, and President Trump used the term “nonessential” when he announced the closing of the U.S.-Canada border in a tweet on March 18.

Perhaps surprisingly, it’s a term that has never been defined precisely by the State Department, which doesn’t provide guidance regarding what is or isn’t essential when it comes to travel. (Similarly Global Affairs Canada and the U.K.’s Foreign and Commonwealth Office, which also regularly use the term, don’t define it in detail.) Instead it is left to individual travelers to decide what family, business, or personal matters are so urgent that they would justify not heeding the advice to stay home.


Because of the relatively long incubation period for COVID-19, anyone who may have been exposed to someone who tested positive for the virus or who traveled to an area of the world where there’s an active outbreak may be asked to quarantine themselves and avoid contact with all other people, typically for 14 days. If that period passes without any signs of symptoms, it’s considered safe to assume the person quarantined wasn’t infected.

Currently the CDC recommends quarantining for travelers arriving into the U.S. (or returning) from 30 European countries (the Schengen area as well as Ireland and the United Kingdom), China, Iran, Malaysia, and South Korea.

Self Isolation

If someone is found positive for COVID-19 but isn’t suffering from symptoms serious enough to require hospitalization, doctors may recommend (or even order) that they isolate in their own home, avoiding all contact with other people. The CDC has a helpful one-page download of the measures that someone who’s self isolating should take, including wearing a face mask whenever they’re in contact with any other person and monitoring their symptoms.

Social Distancing

These are measures intended to be followed by people who haven’t had any known exposure to COVID-19; they’re meant to slow the transmission of the virus. The practice of social distancing can be boiled down to avoiding physical contact with, or even proximity to, other people. Social distancing protects the person practicing it from the possibility of infection while also protecting the public in situations where he or she is unknowingly carrying the virus (for example, with someone who is contagious but asymptomatic).

At its most basic, social distancing requires avoiding large events from concerts to conferences, where the risk of exposure is greatest. Though that risk may be somewhat lower at small gatherings and at bars and restaurants, it remains. This has led to more than 20 states (so far) ordering complete or partial closures or restaurants (in some states take-out or delivery is still allowed).

At its most extreme, and therefore effective, social distancing requires staying at home as much as possible and limiting contact to those who share the same living space. When it is necessary to go outside, most authorities advise keeping a six-foot distance from other people. (The World Health Organization recommends maintaining a distance of at least one meter, or roughly three feet.)

Physical Distancing

Some psychologists and social workers concerned with the isolation that can result from social distancing have encouraged people to adopt the term “physical distancing” instead. The ideas are synonymous, though the hope is that an emphasis on physical distancing will remind people that maintaining social contact through email, telephone calls, video conferencing, and other forms of communication is not only allowed but essential to avoiding feelings of loneliness and isolation.

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John Newton is a writer, editor, and translator who splits his time between Méridia, Mexico, and Brooklyn, New York.
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