A viral outbreak traced back to a live seafood and animal market in the Chinese city of Wuhan, home to 11 million people, continues to spread around the world, with new cases reported in the United States.
So far, 170 people have died from novel coronavirus, and more than 7,800 people have become sick in China, authorities have said. Health officials have identified 68 cases in 15 countries, including the U.S., the World Health Organization reported. These numbers are expected to rise.
Questions remain about the virus’ nature and severity. That is why the World Health Organization last week postponed declaring novel coronavirus a global public health emergency. It is scheduled reconvene Thursday to decide if novel coronavirus now poses such a threat.
Here’s what we know about this illness so far, and some questions public health experts are still asking.
How does novel coronavirus spread?
Novel coronavirus, or 2019-NoCV, belongs to the same family of viruses as the common cold and SARS. Though its geographic origin has been pinpointed, it’s unclear which animal first carried the virus, or how it was transmitted from animals to humans.
Practicing good public health etiquette “goes a long way in preventing all respiratory viral illnesses, including novel coronavirus,” said Sharon Wright, senior medical director and hospital epidemiologist at Beth Israel Deaconess Medical Center in Boston.
To prevent further spread, health officials ask people to cover their noses and mouths when they sneeze or cough, stifling the spray of airborne respiratory droplets — i.e. saliva and mucus — that might spread the virus to others.
On Sunday, the Centers for Disease Control and Prevention elevated its travel precautions, warning people to avoid all non-essential travel to China’s Hubei Province, including Wuhan, and to exercise caution when traveling around the rest of the country. This includes avoiding sick people and all animals in the region, discussing the trip with a health care professional and thoroughly washing your hands with soap and water for at least 20 seconds.
Why has China put cities on lockdown?
China has shut down transportation for 17 cities, including Wuhan, effectively placing 50 million people under quarantine.
The outbreak comes amid Lunar New Year celebrations, “an occasion for extremely widespread travel,” said William Schaffner, an epidemiologist and medical director for the National Foundation of Infectious Diseases. “Celebratory occasions where people get together with friends and family — that’s an ideal condition for transmitting a respiratory virus.” And that poses a significant public health challenge.
There is debate among public health experts about the wisdom of this containment strategy, said Kasisomayajula Viswanath, a scientist and professor of health communication at the Harvard T.H. Chan School of Public Health.
While similar strategies were taken during outbreaks of ebola and H1N1 (or swine flu) virus, Viswanath said China’s “scale of quarantine this time around is unprecedented.”
Before the Chinese government could lock down affected cities last week, several million people left Wuhan alone, Viswanath said, potentially scattering exposure ahead of the quarantine.
“If that is true, it can be a real problem,” he said.
Right now, the Chinese government is in panic mode, said Minxin Pei, an expert on Chinese governance and professor of government at Claremont-McKenna College.
During crises, China stumbles because of “bureaucracy, secretiveness and censorship,” Pei said, leading to initial under-reaction that cost the country’s public health infrastructure time in identifying and containing the virus. Now, the country is lurching into overreaction mode, Pei said. Over the next two weeks, Pei said he anticipates logistical problems, such as not having the capacity to produce enough medical supplies.
“The tragedy is that this could have been dealt with sooner and less costly,” he said. “Things will get worse before they get better.”
What do public health experts still want to know?
After the 2003 SARS outbreak that sickened more than 8,000 people and led to 774 deaths worldwide, China established a surveillance system to monitor pneumonia outbreaks, a red flag for the potential rise of a viral infection.
Epidemiologists have credited China with quickly identifying the pathogen responsible for novel coronavirus, sequencing its genome in weeks and sharing that information with scientists around the world. That helped Japan and Thailand identify its cases, the CDC said.
But Tom Frieden, former CDC director, said China should be more forthcoming with case details.
The global public health community needs a better understanding of how the virus works. After exposure, how long does it take for symptoms to emerge? What risk factors are associated with the virus? Who is most at risk of getting severely ill? Or dying? How does this virus spread?
“The sooner China publishes that information, the safer China will be, and the safer the world will be,” Frieden said.
Coronavirus has been detected in the U.S. Now what?
In the U.S., physicians have diagnosed six people with confirmed cases of novel coronavirus. All but one had traveled recently to Wuhan. The virus spread from a patient in Illinois to her husband, the first instance of human-to-human spread of the virus in the U.S., CDC said Thursday. On Wednesday, the CDC said 165 additional cases are under investigation in more than two dozen states.
More cases are expected to emerge, said Nancy Messonnier, who directs the National Center for Immunization and Respiratory Diseases,but the nation’s immediate health risk level is considered low.
“Risk depends on exposure,” she said. “Right now, we have a handful of patients with this new virus in the U.S. However, at this time in the U.S., this virus is not spreading in the community.” Public health experts said the virus’ incubation period — the time between when a person is exposed to the virus to when symptoms appear — is within 14 days and has not appeared to mutate.
On Jan. 17, the CDC dispatched public health experts to screen passengers arriving at the international airports in San Francisco, New York (John F. Kennedy), Los Angeles, Atlanta and Chicago O’Hare. Out of more than 2,400 people screened, no one tested positive for the illness in those airport checks, according to Messonnier during a call with reporters Tuesday. Since then, the screenings have expanded to 20 airports nationwide, CDC said Thursday.
The CDC also is working to develop and dispatch diagnostic test kits to all states to test respiratory and blood samples more quickly. It currently takes four to six hours to complete a test, but the biggest delay is getting the samples to CDC laboratories, Messonnier told reporters during a subsequent call on Friday. Researchers at the National Institutes of Health also are developing medications and vaccines to combat the virus.
The flu still poses a greater risk to Americans
While the public health community is monitoring coronavirus, medical experts urge the public to remember the nation’s primary health risk this time of year — the flu.
Flu season started early in the U.S. and may be on the upswing, health officials said. This flu season, influenza has led to 8,200 deaths, 140,000 hospitalizations and at least 15 million people getting sick, according to the latest CDC estimates.
Influenza B peaked already and appears to be tapering off, but another strain of the illness — influenza A — may be on the rise, said epidemiologist William Schaffner, medical director for the National Foundation for Infectious Diseases. He advised Americans to get their flu shot and take precautions.
“Don’t linger, get vaccinated this afternoon,” he said. “There’s flu in every state.”