China’s new coronavirus may peter out. Or it might join the flu on the roster of the world’s winter illnesses — a bug that will be routinely vaccinated against. Or it might become a global pandemic, killing millions of people.
Experts don’t have enough information to predict which of these very different scenarios will come to pass. So for now, they are cautious.
“The issue is, we don’t know. And any sort of prediction would be ill-advised,” said the director of National Institute of Allergy And Infectious Disease, Anthony Fauci, at a Friday briefing by the presidential task force on coronavirus. “You really do prepare for the worst possible scenario.”
Coronavirus 2019-nCoV reports began at the start of the year with 41 cases in Wuhan, a city of 11 million people, tied to visitors to a now-shuttered seafood market. As of Sunday, there were 37,592 reported cases of the virus, with 99% of those in China, and 814 deaths, the vast majority of those in Hubei province, home to Wuhan.
But cases have also cropped up in 28 other countries or territories, including one death in the Philippines and 69 cases on a Japanese cruise ship, the Diamond Princess, anchored outside Yokohama.
“It’s hard to believe that just two months ago, this virus was unknown to us,” said World Health Organization director-general Tedros Adhanom Ghebreyesus on Thursday, explaining what still isn’t known about the 2019-nCoV: its true origin, how contagious it is, and how deadly. “To put it bluntly: We’re shadow-boxing.”
“We are at the blind-men-feeling-the-elephant stage of this outbreak,” epidemiologist David Fisman of the University of Toronto told BuzzFeed News. “We obviously have people feeling the virus from different angles right now, and we need to see the whole elephant.”
Those unknowns mean that there’s a wide array of possible outcomes for the outbreak, ranging from a contained event like the 2003 outbreak of SARS (a closely related coronavirus that killed 774 people and spread to a dozen countries) to a seasonal increase in pneumonia among the elderly worldwide, to a widespread pandemic resembling the 1918 flu outbreak that killed at least 50 million people.
Scenario 1: The virus stays mostly in China
WHO officials this week still expressed hope that the Chinese government will largely contain the coronavirus through unprecedented travel restrictions and quarantine in Hubei province and elsewhere that most closely resemble martial law enacted over tens of millions of people. The quarantines began two weeks ago, and the coronavirus is thought to have an incubation period of up to 14 days, which is leading to questions about how well the measures have worked, especially after China locked down Guangzhou City, population 14 million, just this Friday.
In support of a containment scenario, Mike Ryan, executive director of the WHO Health Emergencies Program, noted that while case reports have steadily increased in Hubei province, “we haven’t seen that same acceleration in provinces outside Hubei, and equally we haven’t seen that same acceleration in Hong Kong, and Macau, in Taiwanese people either. I think we’re seeing a relatively stable situation outside Wuhan.”
One big question determining the success of China’s containment — where a deadly outbreak is tamped down by quarantines and hospitalization — is whether the virus is effectively transmitted by people without symptoms. Doctors have recorded mild cases, like a child described in a study who only was revealed to be ill through a genetic test and lung scans, as well as patients who were screened too early in their infection and went on to get seriously ill. Those cases might escape quarantine and increase the spread of the disease, making it “very difficult to stop in China,” Alessandro Vespignani, an infectious disease expert at Northeastern University, told Science.
In the past week, that sort of break-out seemed likely with a New England Journal of Medicine report of a Chinese woman who traveled to Germany on business for a few days, infected four Germans at a work meeting and only felt symptoms after returning home. US health officials cited the case in a White House briefing announcing quarantine of US travelers from Wuhan and forbidding foreigners traveling from China entry into the US. But the case study has since proven overstated, with reports that the woman actually did have a fever and other symptoms while still in Germany, but suppressed them with cold medicine for her business meetings.
Still, Chinese scientists are certain that asymptomatic infections have taken place, said NIAID’s Fauci on Thursday when answering questions from an editor of a scientific journal. He said that he thinks asymptomatic infections are “not the driver of the outbreak,” based on other coronaviruses. There are four common coronaviruses already endemic in people, thought to cause about 10% to 30% of colds, and pneumonia, as well as the more dangerous MERS and SARS, the latter the closest genetic match to 2019-nCoV.
Scenario 2: Another seasonal flu
If the coronavirus does manage to spread widely outside of China, it isn’t necessarily catastrophic. It could turn out to have seasonal behavior, flaring up in winter like the flu. That pattern has been seen in at least two of the common coronaviruses that affect people. If that’s the case for this new one, said Fauci, “when you start getting into the spring weather of April, May, and June, it almost certainly would start to turn around.”
On the downside, that means it would just come back next winter. That happened with the 1918 Spanish flu pandemic that hit the world in two seasonal waves.
Still, the extra time wouldn’t hurt, allowing for clinical trials to test the effectiveness of antiviral drugs used on an emergency basis in the outbreak. China has started two randomized clinical trials of a promising drug called remdesivir, overseen by respiratory disease expert Cao Bin at Beijing’s China–Japan Friendship Hospital. (One of the 12 US patients with the coronavirus tried the drug and recovered a day later.)
“If it keeps going, but tapers down in the Northern Hemisphere over the summer, and then resurges next winter, we are really going to need a vaccine,” Fauci told BuzzFeed News by phone on Saturday.
Several vaccines are already in development. One might prove safe within a year, Fauci said, and then be churned out in large quantities within two years. That’s remarkably fast: A decade ago it would have taken seven years to roll out a new vaccine, he added.
The earliest doses of a new coronavirus vaccine would likely go first to health providers and next to the elderly and people with health risks like lung disease. The US public health system has rolled out rapid mass vaccination programs as recently as 2009, when an H1N1 influenza outbreak jumped from Mexico to the US. CDC’s Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, has compared the spread of that influenza strain, now found worldwide, to the likely eventual spread of the new coronavirus in the US.
With H1N1, she said to reporters on Monday, “by the time we caught it, it was already at our borders.” But with the new coronavirus, “it was caught early before it spread around the world and we had this window of time in which they could intervene to slow it down.” That slowdown gave CDC a chance to roll out a new diagnostic test for the coronavirus, which was approved by the FDA this week.
In the US, there are only 12 cases so far, and all are doing well, according to CDC and the public health department in Wisconsin, where the latest case was announced on Wednesday. Only two of those patients are not travelers from China, and they had direct contact with ill spouses. Case numbers from other countries are similar in size, ranging from 40 patients in Singapore to 1 in Sri Lanka.
“I can’t predict, but I can say we are on a close watch around the world to see if there’s another country that starts to get what we call sustained human-to-human transmission,” CDC Director Robert Redfield said. “Obviously then you try to get the collective effort of the world’s public health community to prevent another China.”
Scenario 3: Deadly global pandemic
Then there’s the worst-case scenario: The relatively few cases popping up in dozens of countries flare up worldwide in the coming months with deadly consequences. It happened in 1957, when a flu pandemic killed 1.1 million people worldwide, and again in 1968, when another flu strain killed about 1 million people.
The death of Chinese physician Li Wenliang on Friday, killed by a coronavirus infection in Wuhan after Chinese authorities had forced him to renounce his December warnings about the outbreak, underlined the reasons for mistrusting China’s odds of having bottled up 2019-nCoV when it originated. (WHO says it has not seen an outbreak in doctors and nurses outside of Wuhan.)
“This is a much bigger thing going on that probably started back in November,” said the University of Toronto’s Fisman, based on both the genetics of the virus, showing how often it has reproduced in human patients, and the trajectory of the increasing case numbers. He and his colleagues suggested in a preliminary study that case numbers on Jan. 31 were likely reporting only 59% of the actual cases, which would point to about 5,000 unreported patients, each one a possible source of more infections. Those numbers suggest that China’s strict internal travel bans have failed to lower the rate at which the average patient infects another person, a number called R0, to below 1, the point at which an outbreak peaks and begins to decline.
That means the new coronavirus might have already skirted containment efforts and might be worse than reported in Hubei province, where some news reports have come of elderly people dying without ever being tested by hospitals. China’s nationwide travel ban, and reports of one province offering a $140 bounty to people who turn in recent arrivals from Wuhan, said Fisman, “are not things you do when you are winning against an outbreak.”
Outside China, some numbers are suspiciously low, with only one reported case from Cambodia, which had direct airplane flights from Wuhan, and few cases in Thailand despite the many planes it receives from China. On Saturday, Singapore minister Lawrence Wong reported a coronavirus patient “without any links to the previous cases or any recent travel history to mainland China,” suggesting the virus was loose in the city-state, a pivotal hub in global travel and commerce.
Seasonality might also not be something to count on, pneumonia expert Richard Wunderink of Northwestern University’s Feinberg School of Medicine told BuzzFeed News, saying he sees pneumonia cases associated with coronavirus cases all year round. “We will see the stress in emergency departments first, where an overload of cases will hit hard right away.”
In that case, the true lethality of the virus — yet another unresolved question — takes on even more weight. From current case counts, a death rate of about 2% has been estimated for 2019-nCoV — not as deadly as SARS, which had a 9% death rate, but still horrific. The Spanish flu outbreak of 1918 had a death rate of 2.5% and preyed on the young. (The new coronavirus instead looks particularly dangerous for people over 65, around 50 million people in the US, or those with health conditions like diabetes.)
Most likely, the new coronavirus mortality rate is much lower than 2%, because of unreported milder cases. A Chinese National Health Commission official said on Monday that the death rate in provinces other than Hubei was 0.16%. That’s still much higher than influenza, which has about a 0.1% mortality rate. (And even then: In the first three weeks of 2020 alone, flu has killed more than 8,000 people in the US.)
On Friday, WHO’s Maria Van Kerkhove said at a news briefing that based on 17,000 cases confirmed by China, around 82% of 2019-nCoV cases are mild, 15% are severe, and 3% are critical. But she cautioned that blood tests to detect antibodies to the virus taken from a broader sample of people in China are needed to reveal the true extent of the outbreak, complicating projections of its future course.
“The one caution about all predictions early in past outbreaks is that they don’t tend to match up with the outcome,” said Fisman, acknowledging his own expectations have worsened as the outbreak has continued. “We still don’t know a lot.”