By Gary Evans, Medical Writer

The first case of person-to-person spread of 2019-nCoV emerging coronavirus in the United States has occurred, with the husband of a previously identified case in Illinois now hospitalized, the Centers for Disease Control and Prevention reported Jan. 30, 2020. The man is the first U.S. case with no history of travel to China.

In a related development, the World Health Organization Thursday declared the outbreak a Public Health Emergency of International Concern, which will now coordinate the response between nations. 

Public health officials recently announced the woman became ill after returning from Wuhan, China, the epicenter of what is threatening to become a global outbreak. She was hospitalized, but her husband then became ill and was also hospitalized. They are both in stable condition.

“We understand that this may be concerning, but our understanding based on what we know right now is that the immediate risk to the American public is low,” CDC Director Robert Redfield, MD, said at a press conference.

The CDC cautioned against over-reaction, like wearing surgical masks in public, because the number of cases in the United States is only six. Limited person-to-person spread also has been seen in nine other countries, as people traveling from Wuhan infect their close contacts, Redfield said.

In addition to Illinois, the other four American infections were in travelers who returned from Wuhan to Washington state, California, and Arizona. All have survived and their contacts are being traced to detect any other transmission.

In a snapshot of rapidly changing numbers, as of January 29, China reported 7,711 cases, including 1,370 cases in serious condition and 170 deaths. Although Wuhan remains ground zero, cases were reported from many other cities in China, including 114 in Beijing, the second most populous city in the world. Including the United States, there were at least 105 cases scattered among many other countries, including Taiwan, Japan, Korea, Thailand, Singapore, Vietnam, Nepal, Malaysia, Australia, France, Canada, Germany, and India.

“We expect to find more cases of 2019-nCoV in the U.S.,” said Nancy Messonnier, MD, director of CDC’s National Center for Immunization and Respiratory Diseases. “We have had multiple states and clinicians reach out to us to establish potential cases, with their labs following up and sending samples if warranted.”

Symptomatic cases with a travel history to Wuhan should don a surgical mask and be evaluated in a private room with the door closed, ideally an airborne infection isolation room, the CDC recommends. Healthcare personnel entering the room should use standard precautions, contact precautions, airborne precautions, and eye protection. Airborne precautions call for use of an N-95 respirator of something equivalent.

The CDC is advising against non-essential travel to China, and travelers from Wuhan are being screened at 20 U.S. ports of entry, including 18 airports. Incoming passengers from anywhere else in China are being given cards reminding them to be alert for respiratory symptoms and fever and immediately seek medical care.

The emerging coronavirus has already passed the case counts for its predecessors, SARS and MERS. However, there are some questions whether 2019-nCoV is spreading as rapidly as it appears or if many previously undiagnosed cases are now being identified because of newly available tests. Advancing this latter theory is Daniel Lucey, MD, MPH, FIDSA, FACP, an infectious diseases physician at Georgetown University Medical Center, who is closely following the outbreak.

On Dec. 30, 2019, China reported an outbreak of respiratory disease in Wuhan. Reports indicate that some of the first patients in China were at a Wuhan seafood market that also sold chickens, bats, snakes, marmots, and other wild animals. However, in reviewing case reports, Lucey theorizes that the virus may have been circulating under the radar for weeks and months before the first cases were linked to the food market.

“It didn’t just suddenly appear in December and somehow mutate and become very contagious,” he says. “My hypothesis is it has been around for several months and it has been sort of accelerating and developing the ability to spread quickly.”

Research is emerging on the epidemiologic measure of viral reproductive ratio – called r-naught. The conventional wisdom is that an r-naught of one or less means viral spread will fade out. Researchers looking at 2019-nCoV said the average r-naught is 2.6, with a range of 1.5 to 3.5. “This implies that control measures need to block well over 60% of transmission to be effective in controlling the outbreak,” they concluded.

To reiterate, the CDC recommends considering 2019-nCoV in a patient with fever, respiratory illness, and coughing who has traveled to the city of Wuhan in the last 14 days (the incubation period) or has been in contact with a confirmed case of the coronavirus. Some facilities are simply asking if patients have been to China, as officials there took the extraordinary step of quarantining Wuhan.

“Can you imagine trying to semi-quarantine a city of 11 million people? What does that mean in real life?” says William Schaffner, MD, an infectious disease expert at Vanderbilt University. “The first three things I thought of were food, medicine, and fuel. How do they get that into a quarantined city?”

Images of rapidly built new hospitals in the area were also unsettling. The real-time spectacle played out somewhat cinematically, with some comparing the outbreak to the movie “Contagion,” which was based in part on the rapid emergence of SARS.

For more on this story see the March 2020 issue of Hospital Employee Health.