Department of Health and Social Care

The virus is an example of a zoonotic infection – one that starts in animals first (in this case, bats) and then is able to be passed to humans (maybe going through another animal – in this case pangolins, scaly anteaters). Other examples of zoonotic viral infections include:

• the variola virus (which causes smallpox)
• HIV (which causes AIDS)
• the Ebola virus
• the influenza virus strains that cause bird flu and swine flu.

The first reported human infections were in Wuhan, China in December 2019. The first reported case outside of China was in Thailand on 13 January 2020, but it wasn’t until 20 January 2020 that it was confirmed that the virus could pass from humans to humans.

On the 24 January 2020, the first cases were reported in Europe (in France).

On 31 January 2020, the first cases were confirmed in the UK. On 4 February 2020, the WHO said ‘We have a window of opportunity. While 99% of cases are in China, in the rest of the world we only have 176 cases’.

As of 10 November 2020, 216 countries and territories across the world have recorded cases. 51,358,916 cases have been recorded.

The main symptoms are: any new, continuous cough; fever; loss of taste; or loss of smell (anosmia). You can find full details of symptoms in adults and symptoms in children on the NHS website.

If you have any of these symptoms, you should arrange an NHS test and self-isolate in line with current NHS guidelines.

For most people, COVID-19 is a mild disease, however for others, it can become life-threatening.

There is a spectrum of severity:

• Some people can have no symptoms at all and feel well, but be carrying (and spreading) the virus.
• People can have a flu-like illness and feel poorly for a short time (between five and seven days), with tiredness, headaches and muscle aches.
• Some people can have symptoms that last a long time. People have reported still feeling unwell even seven months after they were first unwell – this has been called ‘long COVID’.
• Some people can have a more severe illness, leading to hospitalisation. This can potentially cause people to die.

Generally, coronavirus causes more severe symptoms in certain groups of people.

Scientists are gathering more information all the time about which groups of people are at higher risk of a more severe coronavirus infection.

At the moment, the evidence suggests that men are at slightly higher risk than women. People who are older (over 60) are also at greater risk. People from a Black, Asian or minority ethnic background are also thought to be at increased risk of more severe infection; the reasons behind this are complex.

Some people are defined as clinically extremely vulnerable: they’re at very high risk of severe coronavirus. People are identified as clinically extremely vulnerable if they have certain conditions (like specific cancers or Down’s syndrome) or if their doctors have decided to add them to the shielded patients list.

Some people are defined as clinically vulnerable: they’re at a moderate risk of developing complications from coronavirus. These include people who are aged 70 or older, or people aged under 70 with an underlying health condition such as chronic kidney disease, diabetes, or being pregnant.

People are at a low risk of developing complications from coronavirus if they are not in the moderate or high risk groups. 

You can read more about the shielded patients list on the government and NHS websites.

The reasons behind this are complex; they're underpinned by existing social inequalities including economic disadvantage, housing challenges, historic racism, and poorer experiences of healthcare or at work.

Even though the evidence shows that, typically, children and young people have a milder disease, we’re still learning how the virus affects children and young people.

We do know that children and young people can spread the virus in the same way as adults. This means that children or young people could still give it to someone who may have a more serious case of coronavirus.

From March to June 2020, people defined as clinically extremely vulnerable were asked to shield: they were asked to not leave their homes and minimise all face-to-face contact.

From the 1 June 2020, they were allowed to go outside with other members of their household. Shielding was paused from 1 August 2020.

During the national lockdown from 5 November to 2 December 2020, people defined as clinically extremely vulnerable were advised to stay at home as much as possible, except to go outdoors for exercise or to attend essential health appointments. They were also advised to try to stay two metres apart from other people within their household. You can find out more about the guidance for people defined as clinically extremely vulnerable on the government website.

The R number stands for the reproduction number. It’s a way of rating the ability of coronavirus (or any disease) to spread.

The R number is the number of people, on average, that one infected person will pass the virus on to. For example, if the R number is two then, on average, each infected person will infect two more people.

If the R number is bigger than one, then the epidemic is increasing. If the R is smaller than one, the epidemic is decreasing.

The doubling time means the length of time it takes for the number of people infected with coronavirus to double. The more people who have the virus, the higher the R number, and the lower the doubling time.

In the UK, in April, the doubling time was thought to be about five days. With all the prevention measures put into place, this increased to about eight days by September.

The disease can spread from person to person through small droplets from the nose or mouth. These small droplets are released when a person with COVID-19 coughs, sneezes, breathes out, or talks. They can also be spread when a person with COVID-19 touches their nose or mouth.

People can catch COVID-19 by breathing in these droplets. The droplets also land on objects and surfaces around the person. People can catch COVID-19 by touching these objects or surfaces and then touching their eyes, nose, or mouth.

No. There is strong evidence that people who are asymptomatic (who have no symptoms) can still have the virus in their saliva (and other bodily fluids like snot) and pass it to others.

Anyone testing positive, even if they have no symptoms, must self-isolate in line with current NHS guidelines.

When someone with coronavirus coughs, sneezes, talks, or breathes out (or touches their mouth or nose), they spread the virus through small droplets. The virus can live on surfaces.

People can get the virus on their hands when they touch objects such as door handles, pens, and cutlery. They can get coronavirus if they then touch their faces – and it’s been estimated that people touch their faces over 20 times in an hour.

Washing your hands regularly helps to make sure they’re as clean as possible all the time. It’s important to use soap and warm water. The virus sticks to people’s hands because of the natural oils – soap breaks up this oil (which is why your hands may feel dry after you wash them) and the warm water washes the virus down the plughole.

When someone with coronavirus coughs, sneezes, talks, or breathes out (or touches their mouth or nose), they spread the virus through small droplets. This is why older children and adults wear masks in some places.

Most of these droplets can’t travel as far as two metres, so if people stay at least two metres apart they’re less likely to come into contact with droplets.

If someone coughs or sneezes, the droplets will travel further. This is why it’s really important to cover your mouth if you cough or sneeze.

When someone with coronavirus coughs, sneezes, talks, or breathes out (or touches their mouth or nose), they spread the virus through small droplets. Masks catch the virus and stop it getting into the air.

You can watch this video by The Slo-Mo Guys to see how many droplets come out of someone’s mouth when they talk, cough, or sneeze. They show how a mask helps stop these droplets travelling through the air.

It’s especially important to wear a face covering where it’s more difficult to be socially distanced from each other, if you’re indoors, or if there’s not much ventilation.

No. It can be uncomfortable to wear a medical mask or face covering for a long time, but it doesn’t lead to carbon dioxide poisoning or oxygen deficiency (not having enough oxygen).

A swab test collects a sample with a swab, a stick with a fabric tip on the end. You put the swab towards the back of your throat (where your tonsils are) and then you put it up your nose.

The sample from a swab test is usually analysed using the PCR technique.

A saliva test collects a sample of spit (around two millilitres) in a pot. This is very simple and easy to do at home. There’s evidence that the virus first replicates (copies itself) in cells in the saliva glands. Testing saliva means it’s possible to see if someone has coronavirus before they show any symptoms.  

The sample from a saliva test us usually analysed using the LAMP technique.

PCR talks about the way scientists test the sample. It stands for polymerase chain reaction. The PCR technique uses samples taken using a nose and throat swab or samples of saliva.

Scientists use the PCR technique to look for particular parts of the virus. If they’re there, the PCR technique makes lots of copies so that a result can be seen. It only works if the right parts of the virus are present.

The PCR technique has been around for longer than the other tests, and it was the easiest technique to use for a national testing programme. However, it needs specialised equipment and chemicals and people with the right expertise.

LAMP is another way scientists can test a sample. It stands for loop-mediated isothermal amplification. The LAMP technique uses samples taken using a nose and throat swab or samples of saliva.

The LAMP test is similar to the PCR technique but it’s simpler and quicker. Scientists use it to look for particular parts of the virus, usually parts linked with the live virus being present (rather than the bits that can stay behind after people are no longer infectious). If the virus is present in the sample, then an amplification process can take place.

The LAMP technique hasn’t been used to test for coronavirus for as long as the PCR test, but there’s growing evidence that it can identify people who are at risk of giving the virus to others.

Lateral flow tests use swab samples. They also tell people whether the virus is there.

The tests work in a similar way to a pregnancy test: they show a positive line if the virus is detected in the sample. Some ‘false positives’ tests may happen with the versions that are first available, but this is rare.

Testing doesn’t just depend on the number of testing kits available. It also depends on the science labs, machines, and chemicals they need to analyse the kits. There’s a lot of demand for these things all over the world.

Different tests have different advantages and disadvantages. The PCR test has been used for the national testing programme because it was the first technique that was ready to be used for a large number of tests. The newer tests (LAMP tests and lateral flow tests) may provide quicker results and more convenient methods for testing if we are testing large numbers of people. Being able to use saliva as a sample for testing is less invasive than collecting samples using a nose and throat swab.

We will probably need to keep using a variety of tests.

If people test positive, they must self-isolate in line with current NHS guidelines. All positive test results go into the national test and trace database. The NHS test and trace programme aims to contact all positive cases to ask them to isolate and to find out who they might have given the virus to.

A false negative result is when the test says negative even though the person actually has an infectious virus present – the test didn’t detect the virus that’s there.

How likely a test is to give a false negative depends on how sensitive it is. For example, a test with 90% sensitivity will correctly return a positive result for 90% of people who have the disease, but it’ll return a false negative result for 10% of the people who have the disease and should have tested positive.

The different types of tests for coronavirus have different sensitivity levels.

A false positive is when the test result is positive but there is no infectious virus present.

How likely a test is to give a false positive depends on how specific it is. For example, a test with 99% specificity will correctly return a negative result for 99% of people who don’t have the disease, but will return a false-positive result for 1% of the people who don’t have the disease and should have tested negative.

The different types of tests for coronavirus all have high specificity levels, but they vary slightly.

No. The COVID-19 tests will only detect the SARS-CoV-2 virus. National monitoring has shown a large increase in common colds caused by the rhinovirus, which is a completely different virus, over recent weeks.

If someone is self-isolating because a family member or contact has tested positive, then they must continue to self-isolate for 14 days even if they test negative. This is because they may be incubating (growing) the virus – they may still become infectious within the 14 day period.