Coronavirus vs the flu: How they differ and why your winter jab won't help

Since the outbreak of COVID-19, which is caused by the coronavirus, there has been some confusion as to what it is, how it is different to the flu and what the symptoms are for both.

Here, Sky News explains how they are both similar - yet very different.

What is coronavirus?

Coronaviruses are a large family of viruses which may cause illness in animals or humans, according to the World Health Organisation (WHO).

The most recently discovered coronavirus causes COVID-19 and on Wednesday, the WHO declared the outbreak a pandemic, which it defines as the worldwide spread of a new disease.

What is the flu?

Influenza, most commonly known as the flu, is a viral infection affecting the lungs and airways, according to Public Health England (PHE).

Symptoms

Both can result in fever, tiredness and a dry cough - although according to Johns Hopkins Medicine, some patients can also suffer with vomiting at times, diarrhoea, aching body, fatigue and pneumonia.

Patients with the flu can also suffer with a headache, muscle and joint pain, sore throat and a runny nose, according to the WHO.

But with COVID-19, symptoms can also include a shortness of breath.

Transmission

Just like the flu, coronaviruses are respiratory diseases and both can be mild, severe and even cause death - and they can spread when an infected patient coughs or sneezes, spraying small liquid droplets from their nose or mouth, which may contain the virus.

Although it is currently unclear how long COVID-19 can survive on hard objects and surfaces, some experts have suggested its lifespan could be upwards of 24 hours.

The WHO recently warned banknotes may become a public health risk because of the rate at which they change hands, picking up all manner of bacteria and viruses along the way.

Risk groups

Although the WHO says it is still learning about this new virus, it has said COVID-19 adversely affects elderly people and those with pre-existing medical conditions, such as high blood pressure, heart disease, lung disease, cancer or diabetes.

It has also warned those over 60 or with long-term illnesses, to try to avoid crowded places to cut the risk of catching coronavirus.

Influenza is more dangerous for pregnant women, under fives, over 65s, people with chronic medical conditions such as HIV/AIDS, asthma, heart and lung diseases and diabetes.

Treatment

Neither can be treated with antibiotics, which only work on bacterial infections.

Both can be treated by addressing symptoms, such as reducing fever with paracetamol or ibuprofen, or keeping the body cool by taking tepid baths and using cold compresses.

In both COVID-19 and the flu, most people recover, but in severe cases, both can result in death from pneumonia and organ failure.

With the flu, antiviral medicines can be prescribed, but they are not a cure - they can only make the patient less infectious to others, and reduce the length of time you are ill.

Prevention

As this is a new virus, there is currently no vaccine available.

However, the WHO says is it co-ordinating efforts to develop vaccines and medicines to prevent and treat COVID-19, and that possible vaccines and some specific drug treatments are being tested through clinical trials.

The advice widely being given by health experts is:

The WHO says the best way to avoid getting it, is to have the flu vaccine each year, but Public Health England says it will not protect against COVID-19.

PHE has told Sky News that it is because the flu and COVID-19 are "completely different viruses", and that the flu jab is "tailored to the specific flu strain predicted to be most dominant that year".

Deaths

Johns Hopkins University, which is tracking the COVID-19 outbreak, reported on Wednesday afternoon that there were 121,564 suspected or confirmed cases worldwide, and 4,373 deaths - and that 66,239 people have recovered.

Worldwide, annual epidemics of flu result in up to five million cases of severe illness, and between 290,000 to 650,000 respiratory deaths, according to the WHO.

On Wednesday, the UK had its biggest rise in cases after a further 83 tested positive for the disease in the last 24 hours

Eight people have died in the UK

Death rate

Although the WHO says the true death rate for COVID-19 will take some time to fully understand, the current data it has so far, suggests the crude mortality ratio (the number of reported deaths divided by the reported cases) is between 3-4%.

It says the infection mortality rate (the number of reported deaths divided by the number of infections) will be lower.

For seasonal flu, it is usually well below 0.1%, but a big factor is the quality of health care available for some patients (in different parts of the world).

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Common cold versus flu

There are also differences between the common cold and flu, which can be confusing.

Symptoms for both are very similar - including sore throat and headache - but flu can come on suddenly and be more severe, while a cold can appear gradually, according to the NHS.

With a cold, the nose is mainly affected - but with the flu, you can also suffer:

The flu can also leave the patient feeling exhausted and too unwell to go to work or carry on their lives as normal, and they are also likely to spend several days in bed.

In severe cases, a patient can be admitted to hospital and die.

With a cold, you may feel unwell, but not too unwell to stay away from work or normal daily activities.

Other coronavirus developments include: