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COVID-19 A to Z

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

The COVID-19 ID Project aims to improve people’s health literacy about COVID-19 by providing accurate and up-to-date information which will increase knowledge, understanding and confidence and enable people to make good health decisions. 

During the COVID-19 outbreak there are many words and terms being used regularly on news, radio, TV and online that we might never have seen, heard or used before.  To help improve everyone’s understanding we have compiled an A-Z glossary of COVID-19 words and terms with plain English explanations.  This glossary has been adapted (with permission) for a Northern Ireland context from National Adult Literacy Agency Coronavirus COVID-19 words and terms explained in plain English

As COVID-19 is a new and emerging situation we will be updating our glossary as often as possible with relevant words and terms.    If there are any words and terms relating to COVID-19 that you would like to see included in the glossary, please email  

The latest information on the COVID-19 and its effects in Northern Ireland can be found on the following official websites:  

Official information about all aspects of Covid-19  
Health information about Covid-19  
Impact of Covid-19 on health and social care services e.g. appointments with GP, dentist, hospital etc 

Official Government information can be found on the Department of Health website and the Northern Ireland Executive website 



The loss or a change in your normal sense of smell (it can also affect your sense of taste)

On 18th May 2020 the Chief Medical Officers (CMO) from England, Scotland, Wales and Northern Ireland released a statement telling people that Anosmia was now inlcuded as one of the symptoms of COVID-19.  In their statement they said:

  • People will need to self-isolate immediately if they develop a new continuous cough OR fever OR as of today, a loss or changed sense of normal smell or taste (Anosmia).
  • All members of their household must also self-isolate according to current guidelines, unless the person with the symptoms receives a negative test result.

Read the full statement here:

For more information on COVID-19 Symptoms visit:


This is when you do not feel unwell and do not show any symptoms of COVID-19.  However, you can still pass the virus on to others. 


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 if you are: 

  • over the age of 70 - even if you do not have an underlying health condition 

  • Pregnant  

  • Living with chronic (long-term) diseases e.g. asthma, chronic obstructive pulmonary disease (COPD), heart disease, kidney disease, Parkinson’s disease or Multiple Sclerosis 

  • Have a weak immune system due to conditions such as HIV or medicines such as steroid tablets or chemotherapy 

For full details of who is considered at risk, visit NI Direct Webpage Coronavirus (COVID-19): advice for vulnerable people 



A case is a person with COVID-19.  An index case is the first confirmed case in a population, region, or family.  


This slogan is used as part of the advice from the Public Health Agency to help stop the spread of  COVID-19:

  • Catch it: if you cough or sneeze, use a tissue to cover your mouth and nose
  • Bin it: throw it away carefully after use
  • Kill it: wash your hands



The Chief Medical Officer (CMO) is the most senior government advisor on health-related matters and lead medical expert in the Department of Health. The CMO in Northern Ireland is Dr Michael McBride 


These are types of research that study new tests and treatments to understand their effects on human health. They can be used to study the effectiveness and safety of medications (such as vaccines) by monitoring their effects on large groups of people. 


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


Cocooning is a term used by health officials in Republic of Ireland. It describes the practice being used to protect those over 70 or extremely medically vulnerable people from coming into contact with COVID-19. It requires people in these groups to stay at home at all times and avoid any face-to-face contact with others where possible.   

Source: Health and Safety Executive 

In Northern Ireland this is referred to as shielding.  More information on shielding can be found here.    


This occurs where a person who gets COVID-19: 

  • has not travelled to an affected area, and 

  • has no connection to a known case. 

It means that COVID-19 is spreading within the local community  


This term describes a disease that can be spread from one person to another. COVID-19 is a communicable disease.  


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. 


This is where you have a weak immune system (immunosuppressed). There are many things that can cause a weak immune system, including: 

  • Cancer treatment 

  • Conditions such as HIV and AIDS 

  • Medication such as steroids tablets 

  For more information visit NI Direct Coronavirus (COVID-19): advice for vulnerable people 


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. 


When a person tests positive with COVID-19 they are asked to list all the people they've recently been in close contact with.  Those people will then be contacted and provided with information on the symptoms to be aware of, what to do if symptoms develop, and if they need to self-isolate or get tested.

Contacts are identified as being high risk, low risk or no risk. To be high risk you will have to have been in close contact with someone with COVID-19 and have spent more than 15 minutes with them without any personal protection.  This means that those who have casually passed by someone on the street or in a shop will not be considered high risk.

Source: Dr Jackie Hyland, Consultant in Health Protection, Public Health Agency, explains the new PHA pilot programme

Watch this video from the Public Health Agency (PHA) which help explains how contact tracing works

For more information on contact tracing in Northern Ireland click here

England's contact tracing programme is called NHS Test and Trace.  


This means that a disease can be spread from one person to another, typically by direct contact.  This is why we wash our hands regularly and limit our contact with other people during this COVID-19 outbreak. 


This is an early step introduced to prevent the virus from spreading in the community for as long as possible. It involved identifying early cases and trying to establish who the infected person has been in contact with to try and limit the spread of COVID-19. Source: RTÉ website: the terminology of COVID-19 


Process of preventing transmission of COVID-19 from an infected individual to others. Part of the containment strategy includes isolating a person with COVID-19 from other people. 


A coronavirus is a type of virus. COVID-19 is a new strain of coronavirus. It can affect your lungs and airways. The name COVID-19 comes from the year it was first detected (2019) and using letters from CO-rona-VI-rus D-isease. Source: NI Direct Coronavirus (COVID-19): overview and advice 


A new COVID-19 NI information app provides advice and links to vital trusted information. As the situation changes the app will be regularly updated to ensure it stays up to date.  

You can view the app online here or you can download the COVID-19 NI app for both Apple and Android devices using the relevant links below: 


This is one of the two main symptoms of COVID-19, the other main symptom is a high temperature (Fever)

New cough: A cough that you’ve never had before. For those with a chronic cough, this means that the cough will have worsened

Continuous cough: coughing for more than an hour on three or more occasions within a 24 hour period

Source: COVID-19 NI app



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 and delay the impact of COVID-19. Source: RTÉ website: the terminology of COVID-19 


The Department of Health (DoH) is one of nine Northern Ireland Departments.  Find out more about DoH here 


The methods used by healthcare staff to identify a particular illness. E.g. laboratory testing 


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


This is a chemical that kills bacteria. A common disinfectant is bleach.  Disinfectants come in different forms such as liquid, spray bottles, wipes and concentrate. 



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. 


A covering to fit over the nose and mouth.  

In Northern Ireland the Public Health Agency (PHA) recommends that we should think about using face coverings in some situations when we are spending a short amount of time in an enclosed space and we can't social distance from other people.  The main places this is likely to happen will be on public transport (buses and trains) and in shops.

PHA have said wearing a face covering will not be mandatory (it is not required by law to wear a face covering, you can choose whether or not you want to do it).

Even if we do decide to wear a face covering it is still really important we keep:

  •  Social distancing: staying at least 2m (6 feet) away from other people. 
  •  Washing our hands regularly using soap and water
  •  If we cough or sneeze, use a tissue to cover our mouth and nose, throw it away carefully after use, and wash our hands.

That’s still the best way to protect us and others from COVID-19.  Source: Public Health Agency; Face Coverings

The UK Government have provided guidance on how to make a cloth face covering here

Click here to watch a video on how to use face coverings.

See also MASKS


False information is news, stories or hoaxes created to deliberately misinform or deceive readers. Always get your facts through trusted sources. As part of COVID-19 ID Project we are working in partnership with FactCheckNI to fact check unofficial information about COVID-19. CDHN will only publish official or fact checked information about COVID-19 on social media and on our website.  Official websites in NI to get COVID-19 information are at the start of this page.


Fake news is news or stories on the internet or social media that are not true. There are two kinds of fake news: 

  1. False stories that are deliberately published or sent around, in order to make people believe something untrue or to get lots of people to visit a website. These are deliberate lies that are put online, even though the person writing them knows that they are made up. 

  1. Stories that may have some truth to them, but they're not completely accurate. This is because the people writing them - for example, journalists, bloggers or people putting posts up on their Facebook profiles - don't check all of the facts before publishing the story, or they might exaggerate some of it. 

This is happening a lot with COVID-19 with many people publishing these stories in order to get as many shares as possible. 



This is the process of checking that all the facts in a piece of writing, a news article, a speech, a social media post etc are correct. 


Fever or high temperature is one of two main symptoms of Covid-19.  The other is a new or continuous cough. 

A Fever or High Temperature means you are hot to touch on your chest or back.  It is not necessary to have a thermometer to check your temperature. 

A temperature of 38C or more is considered a high temperature (fever) 


  • It's not always easy to take a temperature accurately 

  • If you feel hot or shivery, you may have a high temperature even if a thermometer says your temperature is below 38C  Source: NHS 

Advice from COVID-19 App:  Don’t have a thermometer? Instead check if you have felt unusually hot or cold, shivering at normal room temperature or feverishness. 


This is about reducing the rate at which people become infected with COVID-19. If that rate is pictured as a curve, ideally it would look low and long than high and narrow. This means there is a slowing of the spread of the disease and allows our healthcare system to cope.  

Source: article


Flu is an illness caused by the influenza virus. It occurs every year, usually in winter. Find out more on the flu here



This is a central website for UK government services and information. In NI we have our own local websites where you can find out more under Health and Social Care. NI Direct has links to all  Health and Government information. 



Hand hygiene is a way of cleaning your hands that reduces harmful bacteria on them and stops the spread of harmful germs. The best way to prevent the spread of infections, including COVID-19, is good hand hygiene. This means washing your hands regularly using soap and water and drying them with paper towels.  Watch a video here  

For more information about hand hygiene visit NI Direct Hand Hygiene 


The National Health Service (NHS) in Northern Ireland is referred to as Health and Social Care (HSC) .  There are a number of HSC organisations who work together to plan, deliver and monitor Health and Social Care across Northern Ireland.  They all have websites.  You can find out more here 

Information on COVID-19 can be found on the following HSCNI sites. 

6 trusts 

Official Government information can be found on the Department of Health website and the Northern Ireland Executive website.                                          

To find out more about the structure of our Health system in Northern Ireland see our article with FactCheckNI here 


Everyone should have the same opportunity to enjoy a healthy life but that is not always the case. The conditions in which we are born, grow, live, work and age can affect our health and well-being and these factors are called the Social Determinants of Health (SDOH), see graphic below.

The differences in how people experience the SDOH across our communities are often unfair and unavoidable. These differences are called health inequalities.

Covid-19 has made these inequalities  worse for those already struggling and for others where circumstances have changed because of the pandemic. These include people in low paid or insecure jobs, people living with existing health conditions, people who were already lonely, isolated or experiencing challenges in their homes, like domestic violence, child abuse and addiction to drugs and alcohol.  Many are finding it hard to pay their bills, to buy food and to access the services they need. This can lead to a feeling out of control, increased stress and poorer health and well-being.

For more information on health inequalities including factsheets, policy documents and tool kits visit


Health literacy is about our knowledge, skills, understanding and confidence to be able to use health and care information and services to make good health decisions. Source: Western Health Literacy Partnership 2019.

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


The Health Minister in Northern Ireland has overall responsibility for the Department of Health.  The minister assisted by the Department of Health make policy and legislation for health in Northern Ireland. The Health Minister in Northern Ireland is Robin Swann.   


This is when a high percentage of the community is immune to a disease, usually through vaccination and/or prior illness. When there is a high level of herd immunity against a particular disease then infection stops spreading in the community. This is why people are encouraged to get vaccinations, both to protect themselves and others.   


High temperature or Fever is one of two main symptoms of COVID-19.  The other is a new or continuous cough.  A High Temperature or Fever means you are hot to touch on your chest or back.  It is not necessary to have a thermometer to check your temperature. A temperature of 38C or more is considered a high temperature (fever).


  • It's not always easy to take a temperature accurately. 

  • If you feel hot or shivery, you may have a high temperature even if a thermometer says your temperature is below 38C. Source: NHS 

Advice from COVID-19 App:  Don’t have a thermometer? Instead check if you have felt unusually hot or cold, shivering at normal room temperature or feverishness. 



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


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


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



These are the Government rules to limit contact between people to stop the spread of COVID-19.  In Northern Ireland everyone must stay at home unless they have a reasonable excuse or need for leaving.  If you leave the house, you must stay more than 2m (6ft) apart from anyone outside your household.  This is called social distancing. 

Working with FactCheckNI we have put together some useful information about the rules of lockdown in Northern Ireland.  Find it here.


  • Monday 18th May 2020:  NI Executive announced the first changes to the lockdown rules in Northern Ireland.  Read more here.  
  • Thursday 28th May 2020: This was the date the NI Executive had set down to review the lockdown rules again.  They announced more relaxations that will begin on 8th June if the R Value stays at or moves below 0.9.  Find out more here.   


The World Health Organisation (WHO) currently says only two groups of people should wear protective medical masks:

  • People who are sick and showing symptoms
  • People caring for people suspected to have COVID-19

For more information visit WHO Advice for Public: when and how to wear masks



We all have mental health, just like we all have physical health. Sometimes we feel well, and sometimes we don’t.  Mental health is about how we think, feel and act, and this is always changing.  When our mental health is good, we enjoy being around other people and we feel able to take on challenges and new experiences. But when our mental health is not so good, we can find it much harder to cope


The last few months have been a worrying and challenging time, with so much uncertainty about what will happen and big changes to our everyday lives because of COVID-19.  It’s important we take care of our mental and emotional wellbeing during this time.

A number of COVID-19 Mental health and emotional wellbeing resources are available at


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


in this phase, the aim is to reduce the damage of COVID-19 in the community by implementing a number of measures such as:

  1. providing hospitals with the support they need to maintain essential services as COVID-19 spreads

  1. helping communities to reduce the overall impact of COVID-19 on their lives, businesses and communities


This is the proportion of people who have an illness in the population. It is usually considered in terms of a percentage or per 100,000 people. 


This is the proportion of people who have died from an illness in the population.  It may be expressed as a percentage or per 100,000.  



A number of disease cases higher than what is normally expected.  In 2020, we are currently experiencing a sudden outbreak of COVID-19.  



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. 


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. 


This means people are separated out. For example, when we go outside we must make sure we are 2 metres ( 6 foot) away from the next person.  This is also called social distancing.


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. 



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 – in Northern Ireland if you have symptoms of COVID-19, you'll need to stay at home for 7 days.   

More information is available here  



The R value tells us the average number of people one infected person can pass coronavirus (COVID-19) onto.  For example, if a virus has an R value of 3, it means that every person with the virus will pass it on to 3 other people if we are not doing anything to stop the spread.

To beat COVID-19 we need to keep the R value as low as we can.

Click here to watch a video explaining the R value 


The plan the government will use to start lifting the lockdown rules for example allowing us to meet up with family and friends who do not live with us and reopening some shops and businesses.    

On 12th May 2020 the Northern Ireland Executive released a five-stage recovery plan that explains how they are going to decide to ease rules and slowly move out of lockdown in Northern Ireland.  You can find it here  

We teamed up with FactCheckNI to help explain the five-step plan.  Read our article here

The UK Government have also published a plan for England: Our plan to rebuild: The UK Government’s COVID-19 recovery strategy and the Republic of Ireland Government released their Roadmap for reopening society and business


  • Monday 18th May 2020:  NI Executive announced the first changes to the lockdown rules in Northern Ireland.  Read more here.  
  • Thursday 28th May 2020: This was the date the NI Executive had set down to review the lockdown rules again.  They announced more relaxations that will begin on 8th June if the R Value stays at or moves below 0.9.  Find out more here.   


This means breathing. Lungs help us to breathe. 


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 washing your hands. 

  • Coughing or sneezing into the inner elbow (upper sleeve) rather than into the hand, if no tissues are available. 

  • Keeping unwashed hands away from the mouth, eyes and nose.


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

In Northern Ireland the Government have introduced restrictions on our movements during the COVID-19 pandemic.  These include that no-one may leave their home without reasonable excuse.  

Government guidelines are available here


  • Monday 18th May 2020:  NI Executive announced the first changes to the lockdown rules in Northern Ireland.  Read more here.  
  • Thursday 28th May 2020: This was the date the NI Executive had set down to review the lockdown rules again.  They announced more relaxations that will begin on 8th June if the R Value stays at or moves below 0.9.  Find out more here.   


This means staying indoors and avoiding contact with other people. If you have symptoms of coronavirus infection (COVID-19), however mild, do not leave your home for seven days from when your symptoms started. More information on self-isolation is available here 


Is used to protect extremely vulnerable people from coming into contact with COVID-19.  It requires people who are at a very high risk of severe illness from COVID-19 because of an underlying health condition to stay at home at all times and avoid any face-to-face contact with other people for at least 12 weeks (3 months). The UK Government has provided guidance about shielding that can be found here 


This means you stay away from people, so less people get the virus. Stay at least 2m (6 feet) away from other people.   

Guidance on social distancing can be found here 


COVID-19 is spread through sneeze and or cough droplets.  If you cough or sneeze, use a tissue to cover your mouth and nose, throw it away carefully after use, and wash your hands. Source: PHA Preventing the spread of infection 


There are signs that you might have COVID-19 

The main symptoms to look out for are: 

  • a high temperature – this means you feel hot to touch on your chest or back (you do not need to measure your temperature); 

  • a new, continuous (ongoing) cough – this means coughing a lot for more than an hour, or 3 or more coughing episodes in 24 hours (if you usually have a cough, it may be worse than usual) 

  • anosmia - the loss or a change in your normal sense of smell (it can also affect your sense of taste)



This is a person who infects significantly more people than usual. You can read more about this term in this article in the Guardian. 


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 nose or mouth using a swab. 


This is a person who has symptoms of COVID-19 and can spread it to other people. For more on COVID-19 symptoms visit NI Direct Symptoms of coronavirus (COVID-19) 



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

Anyone over the age 5 in Northern Ireland with symptoms of COVID-19 is now eligible for testing.  For more information (including how to arrange a test) click here 


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 may be coughing or 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. It is used in hospitals to make sure the sickest people are seen by medical staff first.   



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 person’s viral load is simply how much of the virus they have in their body. 

Research is showing that a person’s viral load might determine how sick they will get.  Studies are ongoing to find out more about viral load and COVID-19.  

Source: The Lancet 


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


It is a tiny, living thing (particle) that causes disease and sickness when a person becomes infected with the virus.   


A vulnerable person is someone in need of special care, support, or protection.  During the COVID-19 outbreak vulnerable people are those who may be more at-risk of serious illness if they catch COVID-19.   

A full list of people who are considered vulnerable during the COVID-19 outbreak can be found at here 



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 


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. 


Definitions are taken and adapted from: