What is a coronavirus?

Dr. Babak Ashrafi

Medically reviewed by

Dr Babak Ashrafi

Last reviewed: 14 Apr 2020

Coronaviruses are a group of viruses that all act in a similar way. They mainly cause diseases in animals but, very rarely, a coronavirus makes the jump from animals to humans. The coronavirus causing the current pandemic is a part of this group of viruses and has made this jump to infect humans.


Other similar viruses from the same group include the Middle East Respiratory Syndrome (MERS) and the Severe Acute Respiratory Syndrome (SARS). The current coronavirus is also known as Severe Acute Respiratory Syndrome Coronavirus 2, or SARS-CoV-2 for short.

The coronavirus triggers COVID-19, a disease that affects the lungs as well as other organs, and can be fatal.

What does COVID-19 do to your body?

When the virus enters your body, it attaches itself to cells in the lungs called goblet cells. These produce mucus (phlegm) and affect cilia cells. These are important cells that help prevent your lungs from filling up with debris and fluid such as viruses and bacteria and particles of dust and pollen.

The virus attacks these cells and starts to kill them, which can damage your lungs, so they fill with fluid making it hard for you to breathe.

At this point, your immune system will start to fight off the infection. You may then develop a fever as this is your body's way of creating a bad environment for the virus to live in. Your body may also start to get rid of mucus by coughing.

In some people, particularly those more at risk, the immune system can go into overdrive while fighting the virus and start killing healthy cells as well as the virus. This immune response can lead to organ failure and death.

Learn what to do if you have symptoms of COVID-19

Find out if you have COVID-19 antibodies
Order an antibody test now

Where did the coronavirus come from?

On 31 December 2019, the World Health Organisation's (WHO) China office heard the first reports of a previously unknown virus causing a number of pneumonia cases in Wuhan, a city in Eastern China.

These cases are thought to have been caused by COVID-19. It’s currently thought that it originated in a market where wild animals are sold, although a confirmed source of the strain has yet to be discovered.

Questions about coronavirus? Get free advice from our doctors
Message our doctors

What is the difference between an epidemic and a pandemic?

The virus initially caused an epidemic in China, which means it spread quickly and affected many people at the same time.

As it spread further, the WHO announced that it was a global pandemic. A pandemic is a type of epidemic that spreads worldwide.

The last condition that the WHO declared a pandemic was swine flu in 2009, which is believed to have killed hundreds of thousands of people.

Medically reviewed by:
Dr Babak Ashrafi Clinical Lead for Service Expansion

Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.

Meet our doctors

Last reviewed: 14 Apr 2020

Authorised and regulated by