It is a member of the coronavirus family that has never been encountered before. Like other coronaviruses, it has come from animals. Many of those initially 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.
Have there been other coronaviruses?
New and troubling viruses usually originate in animal hosts. Ebola and flu are other examples – severe acute respiratory syndrome (Sars) and Middle Eastern respiratory syndrome (Mers) are both caused by coronaviruses that came from animals. 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, and there have been human-to-human transmissions in the US and in Germany. As of 6 February, China’s death toll grew to 563, with 28,018 confirmed cases. There remains one additional fatality in Hong Kong and one in the Philippines. The mortality rate stands at 2.1%.
Two members of one family have been confirmed to have the virus in the UK, and a third person was diagnosed with it in Brighton, after more than 400 were tested and found negative. The Foreign Office has urged UK citizens to leave China if they can.
The number of people 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.
Why is this worse than normal influenza, and how worried are the experts?
We don’t yet know how dangerous the new coronavirus is, and we won’t know until more data comes in. 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 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 people should call 111 instead of visiting the GP’s surgery as there is a risk they may infect others.
Is the outbreak a pandemic?
Health experts are starting to say it could become a pandemic, but right now it falls short of what the WHO would consider to be one. A pandemic, in WHO terms, is “the worldwide spread of a disease”. Coronavirus cases have been confirmed in about 25 countries outside China, but by no means in all 195 on the WHO’s list. It is also not spreading within those countries at the moment, except in a very few cases. By far the majority are travellers who picked up the virus in China.
Should we panic?
No. The spread of the virus outside China is worrying but not an unexpected development. The WHO has declared the outbreak to be a public health emergency of international concern, and says there is a “window of opportunity” to halt the spread of the disease. 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.