• Lois Zoppi

COVID-19 terminology for the confusion pandemic

There are a lot of words being thrown around right now, a lot of them urgent and desperate advice from the government to stay at home and limit the spread of COVID-19. But, there’s also a lot of medical terminology that most of us won’t come into contact with until we’re ill ourselves, or, in this case, until a new virus brings the world to a virtual standstill.

Here’s a simple breakdown of all the terminology going viral right now, so you can be sure you know your epidemic from your pandemic and your isolations from your quarantines.

This list is split into two sections: disease spread, and clinical terminology.

Disease spread

Community transmission

Community transmission refers to cases of COVID-19 (or any communicable disease) that arise without any known link to other confirmed cases or outbreak areas.


Endemic refers to a disease that is constantly present in a part of one particular population, but at a low and predictable level. For instance, malaria is endemic in certain countries in Africa, but not in other countries like France.


An epidemic is a sharp increase in disease outbreak in one particular population at the same time. There are different baseline rates for different diseases, which is why we don’t refer to the common cold outbreaks as an epidemic every winter.

Incubation period

An incubation period is how long it takes for a person to become symptomatic after catching COVID-19. At present, the incubation period for COVID-19 stands at 14 days, meaning you could carry and transmit COVID-19 to people you meet without knowing you have the illness.


Outbreaks, like endemics, are sudden increases in disease incidence, but endemics only refer to infectious diseases. Outbreaks can refer to illnesses and diseases caused by environmental factors, too, and refer to rapid increases in a specific time and place.


Pandemic refers to when a disease has global or near-global spread, and has affected numerous countries at the same time.


Self-isolation is when someone with COVID-19, or suspects they may have it, stops all contact with other people while they recover. Those who do not have the illness but are at risk of complications of COVID-19 also self-isolate to protect themselves from transmission.


Quarantining is necessary when a person has come into contact with someone who has a confirmed case of COVID-19. This period of time is used to see if that person develops symptoms, and to stop transmission completely if they do. During quarantine, people should sleep in separate beds, use separate plates and cutlery, and not share bathrooms if possible.

Social distancing

The practice of standing a set distance apart in order to limit the spread of a disease. In COVID-19, this means standing at least 2 metres or six feet away from other people at all times, as the virus is less likely to spread from person to person over this distance.

Clinical terminology

Acute respiratory distress syndrome (ARDS)

ARDS is a life-threatening condition in which the lungs can’t provide enough oxygen to the vital organs. Acute respiratory distress syndrome usually occurs as a result of another illness.


We all remember this from school, right? Alveoli are the air-filled sacs inside the lungs (but only in mammals) where gas is exchanged. COVID-19 binds to a lubrication-creating protein in the cells in the alveoli.

Antiretroviral drugs

In normal gene copying, cells change DNA into RNA, but retroviruses encode its genes in RNA before DNA. In order to spread, retroviruses reverse-code themselves into the DNA of infected cells. Antiretroviral drugs block certain stages of the virus life cycle, which stops the virus from being able to replicate and spread. As such, they do not kill the virus, but instead stop its ability to increase its population until it is undetectable.


A person can carry a disease and not display any symptoms. For instance, many people carry the bacteria for staph infections on their skin, but no symptoms of infection occur. With coronaviruses, this means you can live and work with the virus without coughing, sneezing, or exhibiting any other symptoms. You are still able to spread it to other people even if you aren’t wheezing away.

Case fatality rate (CFR)

The amount of people who die from a disease out of everyone who became infected over a defined period of time. CFR is often used to estimate the severity of a disease.

Clinical trial

A controlled study that investigates how effective a drug, vaccine, or medical device is. Humans instead of animals are used in clinical trials.

Controlled study

Controlled studies test a medical treatment or device against a standard treatment or device whose effects are known already. The control group can receive no treatment, a placebo treatment, or dose comparison treatments.

Related to this term is a randomised control trial (RCT), which is a scientific experiment that randomly allocates different types of clinical treatments being tested to groups of study participants. Through random allocation, any bias in the experiment can be reduced and results can be more accurate.


A coronavirus is a common type of virus that often affects humans. In humans, a coronavirus will often cause upper respiratory tract infections (like the common cold). Coronaviruses are single-stranded RNA viruses.


COVID-19 is the name of the novel coronavirus that developed into a pandemic from December 2019 to April 2020 and onwards. COVID can be broken up into CO (corona) VI (virus) D (disease), and 19 (2019). The World Health Organisation devised the new name and were careful not to include the location of the initial outbreak, any animal sources, or any other related coronaviruses like SARS and MERS, even though there are some similarities between them. This was to reduce the risk of racial stereotyping and prejudice, inaccurate links being made between animal sources, and fear around the terms SARS and MERS.


Epidemiology is a branch of medicine. It studies the patterns in disease spread among defined populations. For instance, the epidemiology of diabetes would show that in the UK, from 2019 statistics, the prevalence (the number of people with a disease) of diabetes stands at 3,319,266.


A state of hypoxia is when the body is starved of oxygen in the tissues. People with /altitude sickness/ (a condition caused by a person ascending to altitude too quickly), can often become hypoxic due to the lack of oxygen available to breath in the atmosphere. Lung conditions can cause hypoxia, and is a risk of COVID-19.


Immunocompromised means that a person has deficiencies in their immune system, which could be due to medical treatments, malnutrition, or illness, and mean that their immune system is not working properly. Deficiencies in the immune system can be temporary or permanent.


Immunosuppression refers to when the efficiency of the fully functional immune system is weakened. Some parts of the immune system suppress other parts of the immune system, and it can occur as an extreme reaction to some medications or treatments.

In vitro

In vitro often refers to experiments or tests that are conducted outside of a living organism, for instance in a petri dish or test tube, for instance, in vitro fertilisation.

In vivo

In vivo refers to experiments conducted inside a living organism. It is the opposite of in vitro.

Morbidity rate

Morbidity rate refers to prevalence of a disease in a specific population, not to be confused with mortality rate, which refers to the death rate from a particular cause.

Novel coronavirus (nCoV)

Novel coronaviruses are simply coronaviruses that haven’t been identified before.


A pathogen is an infectious agent, a germ, or any element that can cause disease.

Powered Air-Purifying Respirator (PAPR)

A powered air-purifying respirator is a type of personal protective equipment to protect people against contaminated air. They can be a hood or a face mask that removes pathogens from the air as it is breathed in so it is safe.


A condition or function relating to the lungs.

Secondary infection

A secondary infection is an infection caused as a result of or after a primary infection or use of a certain medication. For instance, the use of antibiotics can make women susceptible to yeast infections, which are considered a secondary infection.


A process of delivering oxygen and air to the body through a mechanical, medical device. It can take the form of a mask or a tube that is inserted into the trachea to directly supply oxygen to the lungs. Other forms of ventilation include aerating the blood.


The virulence of a pathogen or microbe refers to its ability to infect humans and other organisms and cause damage.


Diseases that stem from animals that can be passed to humans, such as rabies.

Images: Unsplash.

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