Q&A: How dangerous is China’s latest viral outbreak?
An outbreak of a new kind of viral disease in China has led to widespread concern about the risks involved and fears of an official cover-up. A 2002-03 outbreak of severe acute respiratory syndrome (Sars) killed more than 800 people after Chinese officials covered up new cases for months, greatly worsening its spread. That has raised questions over Beijing’s handling of the latest outbreak that began in Wuhan, capital of Hubei province.
What caused the outbreak?
After a patient in Wuhan sought medical help for pneumonia-like symptoms on December 8, dozens of people in the city displayed similar symptoms, mainly fever and breathing difficulties.
Chinese scientists last week said they had identified the cause as a Sars-like coronavirus and that they had shared its genetic sequence — vital for swift diagnosis of further cases — with colleagues around the world. So far, 41 cases of the so-called novel coronavirus (nCoV) have been confirmed in China, although no new infections have been found since January 8.
Before this outbreak, six coronaviruses had been identified in humans. Four cause relatively mild cold-like symptoms while the other two, Sars and Middle East respiratory syndrome (Mers), can kill.
Sars and Mers originally passed to humans through contact with animals — civet cats and camels, respectively. Investigators say most patients in the new outbreak have links to a wholesale seafood market in Wuhan, which has since been closed. Experts believe that mammals traded in the market are the probable source rather than seafood.
What has been the impact?
On Sunday the World Health Organization said seven of the 41 patients were severely ill, while six had been discharged from hospital. One patient, a 61-year-old man previously diagnosed with abdominal tumours and chronic liver disease, died of heart failure after contracting the virus.
“While any death is regrettable, I personally don’t think this will change the dynamics of the outbreak as we knew for a fact that there were many severe cases,” said Lin-fa Wang of the Programme in Emerging Infectious Disease at the Duke-NUS Medical School in Singapore.
Will the virus spread?
Pathogens are far more dangerous when they can be transmitted between people, rather than just being caught from animals. Health authorities tested more than 760 close contacts of the patients and found them to be clear of the virus.
On Tuesday the WHO said: “Preliminary investigations conducted by the authorities have found no clear evidence of human-to-human transmission of the novel coronavirus identified in Wuhan. There has been no evidence [even] of limited human-to-human transmission.”
This makes the Wuhan outbreak different so far from the 2003 Sars epidemic, which spread from patients to medical staff and eventually killed more than 800 people, mostly in China.
Dozens of patients arriving in Hong Kong and Singapore from Wuhan with flu-like symptoms have been checked for the new virus, but no new cases have been found. However, the WHO said on Monday that health authorities in Thailand identified the infection in a tourist who had travelled from Wuhan and is now recovering.
Coronaviruses — so-called because they look like royal crowns under an electron microscope — have a high genetic mutation rate and can rapidly develop resistance to new drugs.
“During the Sars outbreak the virus underwent three phases of human adaptation. We have not seen any adaptation [towards human transmission] yet for this new coronavirus,” said Professor Wang.
However the WHO is preparing for the possibility of a wider outbreak, issuing guidance to hospitals worldwide about infection control in case the virus spreads.
Has there been a cover-up?
The outbreak triggered memories of 2002-03 when Chinese officials covered up new cases of the Sars virus for months, greatly worsening its spread. But domestic and international criticism following the Sars outbreak led to an overhaul of China’s disease control system.
Sir Jeremy Farrar, director of the Wellcome Trust research charity and an expert on disease in Asia, said: “Since Sars, China has absolutely transformed its surveillance system and its transparency in communicating the results. There is no secrecy now.”
He went on: “People have to realise how hard it is to track down a new pathogen like this at the height of the respiratory infection season, even using the latest technology. I offer praise for what the Chinese have done over the past couple of weeks.”
Should I avoid travelling to China?
Not on the basis of what is known at the moment. In the UK, Nick Phin of Public Health England said: “The risk to travellers to Wuhan from this disease is low and we are not advising them to change their plans. In order to minimise the risk of transmission, people travelling to the area should maintain good hand and personal hygiene.”
Hong Kong activated its “serious” response mechanism to the disease last week and, like other parts of the region, has increased screening at airports.
The WHO said on Monday that it “advises against the application of any travel or trade restrictions on China based on the information currently available on this event”.
But if continuing investigations of the coronavirus outbreak show a significant risk of an epidemic, WHO director-general Tedros Adhanom Ghebreyesus may convene a meeting of his emergency committee to consider stronger measures.