It takes five days on average for people to start showing the symptoms of coronavirus, scientists have confirmed.

The Covid-19 disease, which can cause a fever, cough and breathing problems, is spreading around the world and has already affected more than 114,000 people.

The US team analysed known cases from China and other countries to understand more about the disease.

Most people who develop symptoms do so on or around day five.

Anyone who is symptom-free by day 12 is unlikely to get symptoms, but they may still be infectious carriers.

The researchers advise people who could be infectious - whether they have symptoms or not - to self-isolate for 14 days to avoid spreading it to others.

If they follow that guidance - which has already been adopted in the UK and US - it is estimated that for every 100 individuals quarantined for a fortnight, one of them might develop symptoms after being released, Annals of Internal Medicine reports.

What are the coronavirus symptoms?

Coronavirus infects the lungs. The symptoms start with a fever followed by a dry cough. After a week, it can lead to shortness of breath and some people need hospital treatment.

The early symptoms can easily be confused with other winter bugs including colds and flu.

The incubation period - between infection and showing symptoms - lasts up to 14 days, the World Health Organization (WHO) says. Some researchers say it may be up to 24 days.

People will be most infectious when they have symptoms, but there have been suggestions some can spread the virus even before they are sick.

How deadly is coronavirus?

The proportion dying from the disease appears low (between 1% and 2%) - but the figures are unreliable.

Thousands are being treated but may go on to die - so the death rate could be higher. But it may also be lower if lots of mild cases are unreported.

A World Health Organization examination of data from 56,000 patients suggests:

• 6% become critically ill - lung failure, septic shock, organ failure and risk of death
• 14% develop severe symptoms - difficulty breathing and shortness of breath
• 80% develop mild symptoms - fever and cough and some may have pneumonia

Older people, and those with pre-existing medical conditions (such as asthma, diabetes, heart disease), are more likely to become severely ill.

Treatment relies on keeping the patient's body going, including breathing support, until their immune system can fight off the virus. Work to develop a vaccine is under way.

How do I protect myself?

The best thing is regular and thorough hand washing, preferably with soap and water.

Coronavirus spreads when an infected person coughs small droplets - packed with the virus - into the air. These can be breathed in, or cause an infection if you touch a surface they have landed on then your eyes, nose or mouth.

So, coughing and sneezing into tissues, not touching your face with unwashed hands, and avoiding close contact with infected people are important for limiting the spread.

Face masks do not provide effective protection, according to medical experts.

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