Coronavirus (COVID-19) words and terms explained in plain English

The National Adult Literacy Agency (NALA) has compiled the following words about coronavirus (also called COVID-19) with plain English explanations. We hear many of these words everyday on the news, radio, TV and online. We list words from A-Z.

The words and definitions are taken and adapted from:


Last updated: 21 April 2020



This is where you are not showing any symptoms that you have COVID-19. However, you can still pass the virus on to others.


At-risk groups

There are some groups of people who may be more at-risk of serious illness if they catch COVID-19.

You are more at risk of serious illness if you catch COVID-19 and you:

  • are over 60, people over 70 are particularly vulnerable and should cocoon
  • have a long-term medical condition – for example, heart disease, lung disease, diabetes, cancer or high blood pressure, and
  • have a weak immune system (immunosuppressed)
  • have a medical condition that can affect your breathing
  • are residents of nursing homes and other long-stay settings
  • are in specialist disability care and are over 50 years of age or have an underlying health problem

Source: HSE webpage on At-risk groups and coronavirus



Body temperature

The normal adult body temperature is 36.5 to 37 degrees Celsius. A high temperature or fever is 38 degrees Celsius or above.




This is a person with COVID-19.

(An index case is the first documented case in a population, region, or family.)


Chain of infection

This is how an infection spreads from one person to another.

This can also be called chain of transmission.

You can read more on this in the HSE Patient Safety sheet on germs.


Clinical trials

These are types of research that study the effectiveness and safety of medications (such as vaccines) by monitoring their effects on large groups of people.


Close contact

This can mean someone:

  • spending more than 15 minutes face-to-face contact within 2 metres of an infected person
  • living in the same house or sharing accommodation with an infected person

Source: HSE webpage on Symptoms and causes



This refers to a small group of people in a particular space who all have the same disease. For example, a cluster of people in nursing homes or hospitals.



This is where certain groups of people (such as people over 70 and people with health issues) will stay in their homes to avoid contact with any person who may have COVID-19.

More information from the HSE here and watch this video.


Community transmission

This occurs where a person who gets COVID-19:

  • has not travelled to an affected area, and
  • has no connection to a known case.



This means that coronavirus can be spread from one person to another.



This means having two different health conditions at the same time. COVID-19 has been found to be particularly severe for people who have other health issues.


Compromised immune system

This is where you have a weak immune system (immunosuppressed).

There are many things that can cause a weak immune system, including:

  • cancer treatment
  • treatment for autoimmune diseases, such as rheumatoid arthritis, lupus, multiple sclerosis (MS) and inflammatory bowel diseases
  • HIV
  • having an organ transplant or a bone-marrow transplant

 Source: HSE webpage on At-risk groups and coronavirus


Contact – direct and indirect

Contact with someone with COVID-19 can include direct contact and indirect contact which can spread the virus.

  • Direct contact is when you breathe in droplets from an infected person’s cough or sneeze through the air. That’s why keeping your distance to 2 metres apart is important.
  • Indirect contact is when you touch something that the infected person has touched with the virus and it is spread to you. That’s why cleaning regularly touched surfaces like door handles, light switches and so on is important.


Contact tracing

When the health authorities try to find who has been in close contact with someone who has COVID-19 to see who else may be at risk of catching it.

Source: contact tracing explainer



This means that a disease can be spread from one person to another, typically by direct contact. This is why we don’t shake hands with people during this COVID-19 outbreak.



This is a process of infecting or staining something making it impure or spoiled.


Containment phase

Steps introduced to prevent the virus from spreading for as long as possible, such as identifying early cases and trying to establish who the infected person has been in contact with.

Source: RTÉ website: the terminology of COVID-19


Containment strategy

Process of preventing transmission of COVID-19 from an infected individual to others. This means isolating a person with COVID-19 from other people.


Coronavirus COVID-19

Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus.

Source: World Health Organisation


It is new illness that can affect your lungs and airways. Most people infected with the COVID-19 virus will experience mild to moderate respiratory (breathing) illness and recover without needing special treatment.

COVID-19 is spread by sneeze or cough droplets. To infect you, it has to get from an infected person’s nose or mouth into your eyes, nose or mouth. This can be direct (from droplets) or indirect (on hands, objects, surfaces).

Source: HSE Coronavirus Overview

The name COVID-19 comes from the year it was first detected (2019) and using letters from CO-rona-VI-rus D-isease.



Delay phase

In this phase the government has taken measures to reduce the peak impact of the COVID-19 and to slow its spread.

For example, shutting schools and colleges and placing restrictions on public gatherings are measures to reduce the impact on COVID-19.

Source: RTÉ website: the terminology of COVID-19



The way healthcare staff identify a particular illness by examining signs and symptoms.



An illness that affects a person, animal, or plant. It can prevent the body and mind from working normally.



This is a chemical liquid that kills bacteria. A common disinfectant is bleach.





The constant presence of a disease in a population within a certain area.

Source: RTÉ website: the terminology of COVID-19



This is a sudden increase in the number of cases of a disease – more than what’s typically expected for the population in that area.



The study of the spread or pattern of sickness in a group of people.


Exponential growth

This means that numbers increase over time very rapidly as they multiply every day. For example:

  • 2 people infect 2 more people each meaning 4 people are infected.
  • 4 people infect 4 more people each meaning 16 people are infected.
  • 16 people infect 16 more people each meaning 356 people are infected and so on.




False information

False information is news, stories or hoaxes created to deliberately misinform or deceive readers. Always get your facts through trusted sources:

Source: Webwise – what is false information (fake news)

Irish sources:


Fact checkers:



A fever is a temporary increase in your body temperature, often due to an illness. A high temperature is 38 degrees Celsius or above. Your body’s normal temperature is between 36 and 36.8 degrees Celsius.

More on fever here on the HSE website.

‘Flatten the curve’

This means reducing the rate at which people become infected with COVID-19. If that rate is pictured as a curve, they would rather it look low and long than high and narrow.

Source: article

This is our goal as we fight COVID-19 because if we control the spread then we reduce the cases arriving into hospitals at the same time.


Flu (influenza) is a severe infection caused by a virus. The flu virus infects your lungs and upper airways. More on flu here on the HSE website.


G website

This is a central website for government services and information.




Hand hygiene and handwashing

Hand hygiene is a way of cleaning your hands that reduces harmful bacteria on them and stops the spread of harmful germs.

The HSE and the Government have recommended that we wash our hands regularly using soap and water. Sing the ‘Happy Birthday’ song twice while washing your hands – this takes 20 seconds. Watch a video here.

More from the HSE on how to clean your hands and a hand hygiene poster.


Health literacy

Strong health literacy is important as we are dealing with a lot of health information during this COVID-19 outbreak.

It has two elements:

  1. Health services and health care professionals communicate clearly and take account of possible health literacy and numeracy needs.
  2. People understand health information correctly and can make an informed decision

Source: NALA Factsheet on health literacy and numeracy


Herd immunity

This is when a high percentage of the community is immune to a disease, usually through vaccination and/or prior illness.



The Health Service Executive (HSE) provides all of Ireland’s public health services in hospitals and communities across the country.

They are leading the information campaign about COVID-19 and are the best source for information about Ireland.





This is process where a person is made immune or resistant to an infectious disease, usually by giving them a vaccine.


Incubation period

The time between when you are exposed to the virus and when symptoms and signs become obvious.



This occurs when germs enter the body, causing it to display symptoms as it tries to destroy the harmful germs.

Source: HSE Patient Safety sheet on germs.



This is when there is too much information – some accurate and some not. An infodemic can make it hard for people to find trustworthy sources and reliable guidance when they need it.

Source: WHO Situation Report 13, February 2020



The process of separating something from other things.

Self-isolation means staying indoors and completely avoiding contact with other people.  You need to do this if you have symptoms of COVID-19. This is to stop other people from getting it. More information from the HSE.


J  –  none

K  –  none





A state of isolation or restricted access put in place by the State to keep people safe against the spread of COVID-19.




A covering to fit over the nose and mouth to protect against infection from others. The World Health Organisation say that if you are healthy you only need to wear a mask if you are taking care of a person with suspected COVID-19 infection.

More information: WHO Advice for public: when and how to wear masks



This is false or inaccurate information that deliberately intends to deceive.

For example, in mid-March there were messages on WhatsApp that Ireland was going into lockdown. This was false and debunked it here.


Mitigation phase

This phase:

  1. provides hospitals with the support they need to maintain essential services as COVID-19 spreads, and
  2. helps those who are ill in the community to reduce the overall impact of COVID-19 on their families, friends and communities.

Source: RTÉ website: the terminology of COVID-19


Morbidity rate

This is the percentage of people who have a disease in the population.


Mortality rate

This is the percentage of people who have died because of an illness in the population.


N – none





The number of disease cases that is higher than what is normally expected.

In 2020, we are currently experiencing a sudden outbreak of COVID-19 with 531,609 cases since December (As of 26 March, Source: Worldometer





This is when an epidemic spreads between countries affecting a large number of people. In 2020, we are in a pandemic with the worldwide spread of COVID-19.


Personal Protective Equipment (PPE)

This is equipment that will protect the user against health or safety risks at work. It includes for example masks, gloves, gowns and eye protection.


Physical distancing

This means people are separated out. For example, when we go outside we must make sure we are 2 metres (6.5 feet or 3 arm length for an average sized adult) away from the next person.


Pre-existing condition

This means any condition for which the patient has already received medical advice or treatment. For example, diabetes, cancer, lung disease and heart disease. It can also be called an underlying condition.




Quarantine and Self-quarantine

A period of time where a person or animal with a contagious disease is isolated.

Self-quarantine is where you restrict your movements to avoid contact with other people within your home and in social situations for a period of time – it recommended 14 days.





This means breathing. Lungs help us to breathe.


Respiratory hygiene

These are measures to prevent infection such as:

  • Covering your nose or mouth with a tissue when coughing or sneezing and getting rid of the used tissue in a waste bin and wash your hands.
  • Coughing or sneezing into the inner elbow (upper sleeve) rather than into the hand, if no tissues are available.
  • Keeping contaminated hands away from the mouth, eyes and nose.
  • Washing your hands after:
  • sneezing, coughing or blowing your nose
  • having contact with possible contaminated objects or materials such as table tops, smartphone, remote controls.


Restricted movement

This means avoiding contact with other people and social situations as much as possible. It is sometimes referred to as self-quarantine.

Source: HSE webpage on Restricted movements and self-isolation

The latest guidelines from the Government were published on 1 April and are available here.





This means staying indoors and avoiding contact with other people. The HSE says anyone with symptoms should self-isolate for 14 days, as this will help slow the spread of coronavirus.

More information on self-isolation from the HSE here.


Social distancing

This means you stay away from other people so less people get the virus.

How do we do this?

We do this by:

  • keeping a space of 2 metres (6.5 feet or 3 arm lengths for an average sized adult) between you and other people
  • reducing physical connection with people outside the workplace and home
  • reducing the number of people you meet every day
  • avoiding common sleeping areas
  • avoiding crowded spaces
  • working from home if possible

Source: HSE website: Protect yourself and others.

Spread (stop the spread)

COVID-19 is spread through sneeze and or cough droplets.

You could get the virus if you:

  • come into close contact with someone who has the virus and is coughing or sneezing
  • touch surfaces that someone who has the virus has coughed or sneezed on and bring your unwashed hands to your face (eyes, nose or mouth)

Source: HSE website: Symptoms and Causes


Symptoms of coronavirus (COVID-19)

These are signs that you might have COVID-19

The main symptoms to look out for are:

 Source: HSE website: Symptoms and Causes


Super spreader

This is a person who infects significantly more people than usual. This is not a scientific term and has been used by the media.

You can read more about this term in this article in the Guardian.


Supply chain

This is a system of organisations, people, activities, information, and resources involved in moving a product or service from supplier to customer.

In relation to COVID-19, a supply chain is about how food and other products get from a farm or factory into our supermarkets and shops.



A sudden increase in cases of people infected with COVID-19.



This is a small piece of cotton wool used by a doctor or nurse for taking a specimen (sample of something).

If you need a test for COVID-19 a healthcare worker will take a sample from inside your mouth and nose using a swab.

Here is a video of Ryan Tubridy getting a swab on the Late Late Show.

Symptomatic person

This is a person who has COVID-19 and can spread it to other people. They have COVID-19 symptoms – see HSE website: Symptoms and Causes





This is where people with symptoms that could be COVID-19 are checked for the virus by taking a swab from their mouth and nose.

Your GP (doctor) can arrange a test if you need one. Call your GP to be assessed for a test if you have a fever (high temperature – 38 degrees Celsius or above) or chills and one of the following symptoms:

  • a cough– this can be any kind of cough, not just a dry cough
  • shortness of breath

Your GP (doctor) may also arrange a test if you are in one of the priority groups. Read more information on testing on the HSE website.



The act of transferring something from one person or place to another.

In the case of COVID-19, this means transferring the virus from one person to another by coming into close contact with someone who has the virus and is coughing and sneezing. You can also get the virus from touching surfaces that someone who has the virus has coughed or sneezed on.



This is the process of sorting people based on their need for immediate medical treatment and sometimes has to be used in hospitals.




Underlying condition

This means any condition for which the patient has already received medical advice or treatment. For example, diabetes, cancer, lung disease and heart disease. It can also be called a pre-existing condition.

People with underlying conditions are more at risk of serious illness if they catch COVID-19.





This is a product that helps the body’s immune system to fight against infections. Most vaccines are given by an injection, but some are given orally (by mouth) or sprayed into the nose.

There is currently no vaccine for COVID-19.



In medicine, a vector is a carrier of disease.



This is a machine to support breathing. It helps to get oxygen into the lungs, removes carbon dioxide from the body and helps people breathe easier. It can also breathe for people who cannot breathe on their own.



A scientist or doctor who studies viruses and the diseases viruses cause.



It is a tiny, living thing that causes disease and sickness.


Vulnerable person or people

 A vulnerable person is someone in need of special care, support, or protection.

During the COVID-19 outbreak vulnerable people are older people, and those with underlying medical problems like cardiovascular disease, diabetes, chronic respiratory disease, and cancer.




WHO (World Health Organisation)

The authority responsible for public health within the United Nations system (about 53 countries). It has excellent information resources including videos about washing hands and how to social distance.

The website is


WHO Alert on WhatsApp

The World Health Organisation launched WHO Health Alert on WhatsApp.

This is a messaging service that will send you the latest reliable and trusted information and news on COVID-19. This includes symptom information and how to protect yourself. You can also ask questions.

To join using WhatsApp, send the word ‘Hi’ to this number: 00 41 798 931 892.



This is the city in China where the first case of COVID-19 was discovered.


X  –  none

Y  –  none

Z  –  none

You can also download a PDF of this list here.


If you have any other words or ideas to make the explanations above better, please email NALA at  

Keep safe,

All the team in the National Adult Literacy Agency

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