Glossary of Coronavirus terms

Region: Ontario Answer # 7004

Community transmission

Community transmission is one way that a virus can spread. It means that people within a community are spreading the virus to each other.

Contact tracing

Contact tracing is a method used to trace where an infected individual was and who they were in contact with, in order to try and identify others who might have contracted the virus.

Once a person is infected and symptomatic with a disease, the person is asked about their activities and their interactions with others, and a contact list is created. People on the list are contacted and informed of the potential risk. If they are considered high risk, then they may be advised to self-isolate.

Finally, there is contact follow-up, where doctors get in touch with people who came into contact with the infected person to see if they begin to develop symptoms.

Coronavirus, COVID-19 and SARS-CoV-2

Coronaviruses are a common cause of colds and other upper respiratory infections, but this pandemic involves a strain of coronavirus that is new to the world’s human population.

Coronavirus is used as a kind of shorthand these days in some media reports, and the new strain is more accurately called the novel coronavirus. The illness caused by the virus is called COVID-19, also referred to by the World Health Organization (WHO) as coronavirus disease 2019.

Some articles in medical journals use a lesser-known term for the virus: SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2).

The WHO says it’s avoiding that term, since it could be confused with the SARS outbreak in 2003.

Endemic, epidemic and pandemic

A disease that is endemic is one that re-emerges on a seasonal basis, occurring at a predictable rate in a certain area or among a set population, such as malaria.

Epidemic is used when the number of infections rises above what is normally expected in a certain population or region. An outbreak is basically the same thing as an epidemic, although the term is often used to cover a more limited geographic area, according to the Centers for Disease Control and Prevention (CDC).

Pandemic relates to the geographic spread of a disease. The WHO designated COVID-19 as a pandemic on March 11, 2020 because it had spread to several countries.


A geographic area (such as a city or province) where an outbreak is most prevalent.


Flattening the curve

The curve refers to the curve or spike of a disease as it is represented on a graph. Flattening the curve means slowing down the spread (which flattens the curve on a graph) so that health care providers can cope with severe cases. For example, although a hospital may be able to handle 20,000 new COVID-19 patients, it may only be able to do so over the course of 6 months vs two-weeks. So, slowing down the spread would allow those that need assistance from the health care system to receive it. In addition, it allows others who are sick or injured unrelated to COVID-19, to receive the care they need.



PPE is short for personal protective equipment.  For health-care workers, it can include isolation gowns, foot covers, eye gear, face masks, face shields and gloves.



R0, pronounced “R-naught” is a measurement used to describe the intensity of an outbreak. R0 is only used when everyone is vulnerable to a disease, meaning no one has had the disease before, and therefore has not been vaccinated. As a result, there is no way to control the spread.

An R0 value of 1 means that each infection will cause one new infection. If it’s greater than 1, each infection will cause more than one new infection. This could create a potential epidemic. The outbreak in China had an early R0 value estimate of 1.4 to 3.9.


Presumptive and confirmed cases

A presumptive case means that a local health agency has received a positive test result from a patient. But the test needs to be validated with a second test. Some provincial labs, such as those in Ontario, British Columbia, Quebec and Alberta, conduct the second test whereas other provinces need to send a sample to the National Microbiology Lab in Winnipeg. Once two tests have come back positive, it is a confirmed case.



An infection case is considered resolved when a person is no longer infected with the virus.


Self-isolation and Quarantine

The terms are often used interchangeably. But health officials sometimes distinguish between “quarantine” and “isolation,” which can be both voluntary and mandatory. In both cases, those isolated need to stay at home and keep away from people who are not sick.

Self-isolation applies to people who are known to be infected.

Quarantine (sometimes referred to as shelter-in-place in the United States) describes separating and restricting the movement of people who may have been exposed to a contagious disease to see if they become sick. People who are quarantined could be healthy and are not necessarily infected. People are asked to stay at home with only limited exceptions, such as briefly shopping for essentials or going outside for exercise while still staying away from others. The onset of the Coronavirus is within two-weeks. So, if the quarantined person has not become sick by then, their quarantine is over.


Social distancing / Physical distancing

Social distancing, now referred to more accurately as physical distancing, means keeping a physical distance of at least 2 metres from other people.


Testing: Nasopharyngeal vs. Oropharyngeal swabs

To be tested for the virus, a sample by swabbing must be collected in one of two ways:

  1. Nasopharyngeal swab – which is inserted up the nostril, or
  2. Oropharyngeal swab – which is inserted in the mouth and a sample is taken from the back of the throat.

For the latest information, visit Health Canada, your Provincial Ministry of Health, and our related links and resources.


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