Coronavirus Moving Towards A Worldwide Pandemic – Based on what they have seen so far, many researchers think it’s probably too late to contain the virus. “As the virus continues to spread in China, the risk of exportation to other countries grows and sooner or later we will see it spread in another country,” Aavitsland says.
So far there has been no sustained transmission outside of China, but Lipsitch expects that to change: “I would be really shocked if in 2 or 3 weeks there wasn’t ongoing transmission with hundreds of cases in several countries on several continents.”
If the virus does spread to all corners of the world in a pandemic, several questions will loom large: What percentage of the population will become infected, and of those, how many will get very sick or die? More severe cases place heavier demands on health care systems—hospitals in Wuhan are already overwhelmed—and result in greater fears and disruption of daily life.
A deadly pandemic might force the world to make stark choices about fair access to medicines or vaccines, if they become available. It might also lead to widespread restrictions on domestic travel akin to those already in force in China, Aavitsland says.
If, on the other hand, 2019-nCoV resembles the common cold or a mild flu, the spread of the virus would be less alarming. Existing travel bans likely would be lifted.
Understanding the severity and case fatality rate is a challenge with any new pathogen. When a new influenza strain emerged in 2009—and went on to cause a pandemic—many worried it might turn out to be a nasty variety. It took months to establish that the new virus killed only about one in 10,000 patients.
So far, mortality among known 2019-nCoV cases is about 2%, and some reports say 20% of infected people suffer severe disease. But these figures may overlook tens of thousands of people with mild disease—say, a sore throat or a low-grade fever—who never seek medical care and may not even know they were infected with 2019-nCoV.
Many may have no symptoms at all. “So what looks like a horrific disease may be the horrific tip of a very large iceberg,” Lipsitch says.
The fact that four Japanese evacuees were asymptomatic is a case in point. Studies in China have also reported some cases with few or no symptoms. What’s missing is a large study in China, Lipsitch says.
He suggests some fraction of the tests that are available in a place with many cases should be set aside for that purpose. (Current recommendations in China call for testing people with clear symptoms only.)
If indeed 2019-nCoV becomes pandemic, humanity may be stuck with it indefinitely. After spreading far and wide, the virus might become endemic in the human population, just like four other coronaviruses that cause the common cold, and occasionally cause fresh outbreaks. How much death and disease it would cause is anyone’s guess.
The silver lining of the epidemic is that scientists have collected and shared information at record speed. “Every day that goes by we know more and every day that goes by we can do better modeling,” Vespignani says. “Unfortunately, this beast is moving very fast.”