Distancing, isolation, quarantine, lockdown: What’s the difference?

Thanks to the COVID-19 outbreak, we’re hearing a lot of medical jargon. If you want to stay safe, you need to know what it means
By Sahil Gupta - Published on Mar 17, 2020
People wear masks as a precaution due to the coronavirus outbreak as they wait for the arrivals at the international terminal at Toronto Pearson International Airport on January 25. (CP/Nathan Denette)



Social distancing. Self-isolation. Quarantine. Lockdown.

Over the past two weeks, our social lingo has started to sound like a clinical-epidemiology textbook. Still, you might not yet know what many of the terms mean — or you might be murky about the distinctions. I’m an emergency-room doctor, and even I’ve had to clarify my understanding of them. 

As the number of COVID-19 cases in the province grows, it’s important to have a basic grounding in the concepts that will shape our experience of the pandemic. I spoke with Aisha Khatib, the clinical director of a travel-medicine clinic and a physician at St. Michael’s Hospital in Toronto, about what the different public-health terms mean and how they apply to Ontarians. 

Social distancing

Khatib says that the purpose of social distancing is to decrease the transmission risk. It started with bigger groups of people, such as those at concerts and hockey games, but right now it means avoiding all non-essential social activities. You can still get groceries and go for walks, but you should avoid going to restaurants or parties. She says to “avoid physical contact with people and keep your distance from people of at least two metres apart and avoid anyone who’s sick.”

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At this stage, we should all be actively practising social distancing, regardless of how we feel right now.

If you do need to go somewhere, make sure you wash your hands frequently and avoid anyone who is sick. You do not need to get tested for COVID-19 to see whether you should be social distancing. This is our new default. 

The majority of people — up to 80 per cent — who get COVID-19 will not need hospitalization. But about 20 per cent will, and roughly 5 per cent of those who become infected will require intensive care. Unless we all adopt social distancing, Khatib says, “our capacity in hospitals won’t be enough” to take care of everyone.

The point of social distancing is to prevent those numbers from peaking and to “flatten the curve” of infections over time so that we won’t overwhelm our health-care capacity. Even with social distancing, a similar number of people may end up being infected, but that will happen over a much longer period — meaning there will be a hospital bed left available to treat them. 


While everyone should be social distancing, Khatib says, there are two types of people who should be self-isolating. 

The first is someone who’s travelled outside Canada or has been in close contact with someone who’s ill and has travelled outside Canada in the past 14 days. Members of this group don’t have to show symptoms or feel sick — the measure is precautionary. They should, however, limit time outside the home, avoid transit, and limit physical contact with others. 

They should also self-monitor to see whether they develop respiratory symptoms, which include coughing, sneezing, fever, or shortness of breath. If they get sick, they should not go directly to their family doctor or to a walk-in clinic: instead, they should contact public health or their doctor, or go to a COVID-19 assessment centre to see whether they require further testing. 

The second category of people involves those already showing respiratory symptoms. At this stage of screening in Ontario, if these people haven’t travelled or have not been in contact with someone who’s ill and travelled outside Canada, they should stay home and self-isolate. They don’t need testing for COVID-19 unless they are immunocompromised or over the age of 60. (There has as yet been no formal recommendation related to those groups.)


These are people who have been tested for COVID-19 (a “person under investigation,” or PUI) and are awaiting results or have tested positive for COVID-19. Khatib says that those who fall into this group should be at home. They should avoid contact with others as much as possible, and their caregivers must take all precautions given by public health.

If someone in this group needs to go back to the hospital, they should inform public health and avoid public transit or taxis when travelling there.


According to Khatib, a lockdown is intended to stop people from moving between places. It is a politically enforced measure instead of a public-health policy, and could involve cancelling flights, closing borders, and shutting restaurants and cafés. It could also mean recording the movement of people from place to place in a city. The idea is for the government to reduce the flow of people to curb transmission.

Khatib says that, ultimately, all “these [measures] are preventative public-health measures to decrease transmission.” While people may be uncomfortable with disruption — and it can be hard to change what you’re doing if you don’t feel as if the pandemic personally affects you — they’re extremely important for overall public health.

She adds that “aspects of social distancing have real concern for social isolation that comes with it” and that we should be calling and checking in on people. If you are healthy and practising social distancing, see whether you can help drop off groceries and supplies to those who should be self-isolating. But, even if you’re healthy, keep your distance — it’s an altruistic move for the greater good.

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