Coronavirus terms explained

Luke James
Group Deputy Chief Medical Officer and Director of Healthcare Transformation
14 April 2020
Next review due April 2023

As we all do our best to learn a new way of life for the coming months, it can sometimes feel as though we have a whole new language to learn too. Many of the words and phrases associated with coronavirus will also be new to us. But it’s important to make sure we’re all fully informed so we can protect ourselves and others. Here I’ll explain some of the common terminology you might hear when talking about coronavirus.


Coronaviruses are a large family of viruses that can cause symptoms in your airways and lungs. Although they’ve dominated the headlines in recent months, different types of coronaviruses have actually been around for some time. Some cause mild symptoms like the common cold, while others are responsible for severe diseases like SARS and MERS. But the particular coronavirus that’s making people ill at the moment hadn’t been discovered before. They’re called coronaviruses because of their characteristic shape – a circle surrounded by a crown (corona).


SARS-CoV-2 is the official name given to the newly discovered coronavirus. This stands for Severe Acute Respiratory Syndrome Coronavirus 2. It’s different to the SARS virus you may have heard of before, which caused a disease outbreak in 2003.


If you become ill and experience symptoms because of the SARS-CoV-2 coronavirus – you are said to have COVID-19. COVID-19 is the name given to the respiratory disease caused by SARS-CoV-2. It stands for Coronavirus Disease 2019.


The word respiratory is used to describe the system of your body responsible for breathing. It takes in oxygen and removes carbon dioxide. This includes your mouth and nose, throat, windpipe, lungs and airways.

New and continuous cough

A high temperature and/or a new and continuous cough are the two main symptoms of COVID-19. A new and continuous cough means coughing a lot for more than an hour, or three or more coughing episodes in 24 hours. If you usually have a cough, it may be worse than usual.

High-risk or vulnerable person

A vulnerable person is someone who is at an increased risk of severe illness if they get coronavirus. This includes people who are aged 70 or older, pregnant or already have an underlying health condition.

An extremely vulnerable person is someone who has a very high risk of severe illness if they get coronavirus. For example, if you have HIV or AIDS, are undergoing cancer treatment such as chemotherapy, or have had a solid organ transplant.

You can find the full list of vulnerable and extremely vulnerable people and underlying health conditions on the website. You might also hear the terms comorbidity and immunocompromised associated with high-risk and vulnerable people.


Comorbidity means you have more than one disease or health condition. They may or may not be related to each other. An example might be if you have diabetes as well as high blood pressure.


If you are immunocompromised, it means that your immune system (the system of your body that fights off harmful diseases) is weakened. This means it’s not as strong at fighting off illness. This might be because you have a condition like HIV or AIDS, you’re having treatment for cancer such as chemotherapy or radiotherapy, or you’re taking medication that suppresses your immune system.

Incubation period

It is possible to have a virus and not know, because you’re not showing any symptoms yet. The incubation period is the time between catching a virus and when you first begin to have symptoms. The incubation period for coronavirus is between one to 14 days, but is most commonly around five days.


A vaccine is a medicine that helps to protect you from disease. It teaches your immune system to recognise and fight off harmful invaders, like bacteria and viruses. They do this by introducing a tiny amount of the germs that causes a disease into your body (usually with an injection or nasal spray). This stimulates your immune system to make antibodies to this germ. So, if you come into contact with the germ again in future, your immune system will recognise it and be prepared to fight it off. Unfortunately, there’s no vaccine for coronavirus yet. But there are lots of clinical trials underway to develop one.


The word endemic refers to a disease that is considered very common or usual in a particular group or area. For example, chickenpox is endemic in children, just as malaria is endemic in hot countries.


An outbreak of a disease means that more people suddenly become ill with the disease than would normally be expected in one area.


An epidemic is similar to an outbreak, in that it means more people have suddenly become ill with a disease than usual. But, an epidemic also means the disease has spread across a much wider area.


A pandemic is when a disease not only spreads between exceptionally large numbers of people and across regions, but throughout the world too. COVID-19 has now been officially declared as a pandemic.


PPE stands for Personal Protective Equipment. This is the equipment used by health and social care workers to protect themselves from catching or spreading infections. It includes respirators, surgical masks, gloves, goggles, face shields, gowns, aprons and other equipment.

There is currently a global shortage of PPE. So it’s only recommended to wear a mask if you have symptoms of coronavirus, or if you’re responsible for looking after someone who may have coronavirus.


A respirator is a special protective mask that healthcare workers wear over their nose and mouth to stop them breathing in harmful particles like viruses. Respirators are different to the face masks you might see worn by the public. They fit more securely around your face and are specially designed to filter the air you breathe.


A ventilator is a machine that helps a patient to breathe. It pumps air in and out of your lungs if you’re struggling to breathe on your own.


Isolation is when someone who is unwell separates themselves from healthy people to stop the disease from spreading. That’s why it’s important to stay at home and self-isolate if you or someone you live with has symptoms of coronavirus. You can find out how long you need to stay at home for on the website.

Social distancing

Social distancing has been introduced in many countries to help slow the spread of coronavirus between people. It means avoiding face-to-face contact, social gatherings, public transport, any non-essential activities and working from home wherever possible. It also means staying at least two metres (six feet) apart from others if you do go out for essential activities.


Quarantine is used for people who are not unwell, but who have recently been exposed to coronavirus. An example would be if you’ve recently returned from an overseas country which has confirmed cases of coronavirus. Even if you don’t have any symptoms and are feeling well, you may still have to isolate yourself at home. This is to stop the virus spreading to healthy people if you have it without realising, or to see if you develop symptoms.


The term lockdown is being used to describe shutting down all non-essential activities in order to slow the spread of coronavirus. This can look different for different countries, but could include closing down schools, businesses, restaurants, gyms and cinemas. It may also mean stopping travel, instructing people to work from home where possible. This includes only leaving home for essentials such as food, medicine, exercise or to care for a vulnerable person.

Luke James
Dr Luke James
Group Deputy Chief Medical Officer and Director of Healthcare Transformation

    • COVID-19: epidemiology, virology and clinical features. Public Health England., updated 30 March 2020.
    • Coronavirus. World Health Organization., accessed 1 April 2020.
    • Vaccines. World Health Organization., accessed 2 April 2020.
    • Vaccines: The basics. Centers for Disease Control and Prevention., last reviewed March 2012.
    • Q&A on coronaviruses (COVID-19). World Health Organization., published 9 March 2020.
    • Introduction to epidemiology: Epidemic disease occurrence. Centers for Disease Control and Prevention., last reviewed May 2012.
    • Guidance on social distancing for everyone in the UK. Public Health England., updated 30 March 2020.
    • Comorbidity. Encyclopaedia Britannica., accessed 3 April 2020.
    • Coronavirus. Encyclopaedia Britannica., accessed 3 April 2020.
    • Immune system disorder. Encyclopaedia Britannica., accessed 3 April 2020.
    • Symptoms and what to do: Coronavirus (COVID-19). NHS., last reviewed 2 April 2020.
    • COVID-19 personal protective equipment (PPE). Public Health England., updated 2 April 2020.
    • Stay at home: guidance for households with possible coronavirus (COVID-19) infection. Public Health England,, updated March 2020.
    • Clinical management of severe acute respiratory infections when novel coronavirus is suspected: what to do and what not to do. World Health Organization., accessed 3 April 2020.
    • The Health Protection (Coronavirus, Restrictions) (England) Regulations 2020. The National Archives on behalf of HM Government., published 26 March 2020.
    • Quarantine and isolation. Centers for Disease Control and Prevention., accessed 3 April 2020.
    • Human respiratory system. Encyclopaedia Britannica., last updated February 2020.

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