What you should know about the coronavirus

There’s a novel coronavirus – a member of the coronavirus family that has never been encountered before.

Like other coronaviruses, it has come from animals. Many of those infected either worked or frequently shopped in the Huanan seafood wholesale market in the centre of the Chinese city, which also sold live and newly slaughtered animals.

New and troubling viruses usually originate in animal hosts. Ebola and flu are other examples.

What other coronaviruses have there been?

Severe acute respiratory syndrome (Sars) and Middle Eastern respiratory syndrome (Mers) are both caused by coronaviruses that came from animals. Although Mers is believed to be transmitted to humans from dromedaries (Arabian camels), the original hosts for both coronaviruses were probably bats. In 2002, Sars spread virtually unchecked to 37 countries, causing global panic, infecting more than 8,000 people and killing more than 750. Mers appears to be less easily passed from human to human, but has greater lethality, killing 35% of about 2,500 people who have been infected.

What are the symptoms caused by the Wuhan coronavirus?

The virus causes pneumonia. Those who have fallen ill are reported to suffer coughs, fever and breathing difficulties. In severe cases there can be organ failure. As this is viral pneumonia, antibiotics are of no use. The antiviral drugs we have against flu will not work. If people are admitted to hospital, they may get support for their lungs and other organs as well as fluids. Recovery will depend on the strength of their immune system. Many of those who have died were already in poor health.

Is the virus being transmitted from one person to another?

Human to human transmission has been confirmed by China’s national health commission. As of 30 January, the death toll in China stands at 170, with more than 7,500 confirmed cases of infections. In the past week, the number of confirmed infections has more than tripled and cases have been found in 13 provinces, as well as the municipalities of Beijing, Shanghai, Chongqing and Tianjin. The virus has been confirmed outside mainland China, in Hong Kong, Macau, Taiwan, and in Japan, Nepal, Singapore, South Korea, Thailand, the US, and Vietnam. Two members of one family have been confirmed to have the virus in the UK, after more than 160 were tested and found negative. The actual number to have contracted the virus could be far higher as people with mild symptoms may not have been detected. Modelling by World Health Organization (WHO) experts at Imperial College London suggests there could be as many as 100,000 cases, with uncertainty putting the margins between 30,000 and 200,000.

How worried are the experts?

There were fears that the coronavirus might spread more widely during the week-long lunar new year holiday, which started on 24 January, when millions of Chinese travel home to celebrate, but the festivities have largely been cancelled and Wuhan and other Chinese cities in Hubei province are in lockdown. At the moment, it appears that people in poor health are at greatest risk, as is always the case with flu. A key concern is the range of severity of symptoms – some people appear to suffer only mild illness while others are becoming severely ill. This makes it more difficult to establish the true number of infected people and the extent of transmission. But the authorities are keen to stop the spread and anxious about whether the virus could become more potent than it so far appears to be.

Should I go to the doctor if I have a cough?

Unless you have recently travelled to China or been in contact with someone infected with the virus, then you should treat any cough or cold symptoms as normal. The NHS advises that there is generally no need to visit a doctor for a cough unless it is persistent or you are having other symptoms such as chest pain, difficulty breathing or you feel very unwell.

Why is this worse than normal influenza?

We don’t yet know how dangerous the new coronavirus is, and we won’t know until more data comes in. The 170 deaths from about 7,700 reported cases means the mortality rate is around 2%. However, this is likely to be an overestimate since many more people are likely to have been infected by the virus but not suffered severe enough symptoms to attend hospital, and so have not been counted. For comparison, seasonal flu typically has a mortality rate below 1% and is thought to cause about 400,000 deaths each year globally. Sars had a death rate of more than 10%. Another key unknown, of which scientists should get a clearer idea in the coming weeks, is how contagious the coronavirus is. A crucial difference is that unlike flu, there is no vaccine for the new coronavirus, which means it is more difficult for vulnerable members of the population – elderly people or those with existing respiratory or immune problems – to protect themselves. Hand-washing and avoiding other people if you feel unwell are important. One sensible step is to get the flu vaccine, which will reduce the burden on health services if the outbreak turns into a wider epidemic.

Should we panic?

No. The spread of the virus outside China is worrying but not an unexpected development. It increases the likelihood that the WHO will declare the outbreak to be a public health emergency of international concern. The key issues are how transmissible this new coronavirus is between people and what proportion become severely ill and end up in hospital. Often viruses that spread easily tend to have a milder impact.

Healthcare workers could be at risk if they unexpectedly came across someone with respiratory symptoms who had travelled to an affected region. Generally, the coronavirus appears to be hitting older people hardest, with few cases in children.