The World Health Organization (WHO) declared the 2019 novel coronavirus (2019-CoV) outbreak in China a Public Health Emergency of International Concern (PHEIC) on Jan. 30. WHO emphasized China will not be isolated from the global community, which can happen after a PHEIC is issued.

“[Nations] implementing additional health measures that significantly interfere with international traffic (refusal of entry or departure of international travelers, baggage, cargo, containers, conveyances, goods, and the like, or their delay, for more than 24 hours) are obliged to send to WHO the public health rationale and justification within 48 hours of their implementation,” the announcement stated. “WHO will review the justification and may request countries to reconsider their measures. WHO is required to share with other States Parties the information about measures and the justification received.”1

Unfortunately, that already was happening with the rapid expansion of cases, and China will likely become more isolated until cases begin to decline.

“The decision was anticipated. I think it makes formal what had been happening already,” says William Schaffner, MD, an infectious disease physician at Vanderbilt University Medical Center. “Namely, travel to and from China was being interrupted informally in many circumstances. Our own university, for example, has let all students know that they were not to go to China on any kind of scholarly pursuit. That’s prudent, of course. This will have major economic implications for China, and it’s unfortunate that it has been instituted. In effect, it puts a country in quarantine.”

WHO will dispatch a multidisciplinary team to China to review and support efforts that will investigate:

• the source of the outbreak;

• the clinical spectrum of the disease and its severity;

• the extent of human-to-human transmission in the community and in healthcare facilities;

• the current efforts to control the outbreak.

WHO particularly emphasized the importance of finding the source, to rule out hidden transmission and to inform risk management measures. As with SARS and MERS, 2019-nCoV likely is from an intermediate animal host that contracted the virus from bats. WHO emphasized the need for enhanced surveillance in regions outside the epicenter in Hubei province, including pathogen genomic sequencing, to understand whether local cycles of transmission are occurring.

One infectious disease expert who is closely following the outbreak theorizes that 2019-nCoV has been circulating for some time, well before the first cases were discovered in the city of Wuhan.1 A recently published study of 41 cases suggests infections were occurring earlier in November, and perhaps October, but there was no available diagnostic test at that time,2 says Daniel Lucey, MD MPH, FIDSA, FACP, an infectious diseases physician at Georgetown University Medical Center.

“I think this outbreak started before the December outbreaks in the seafood and live animal market,” he says. “That paper shows 41 patients and what day they became symptomatic. The very first patient became sick on Dec. 1. The most important thing is that the patient had no exposure to that seafood market. In fact, 14 of the 41 patients had no exposure to the seafood market. It didn’t start with the seafood market in Wuhan. It started somewhere else. How far back does it go? Is there a chain of initial cases that we didn’t know about, maybe from other markets? Also, to me, that explains why there is such rapid spread now to all the other provinces and other countries: because the virus has been around for a while, maybe even since September.”

In the absence of a test, prior cases were likely assumed to be pneumonia and flu that are common in the winter months in China, he said.

“They developed the rapid diagnostic test after they first discovered the virus on Jan. 7,” Lucey explains. “Now, they are testing all of these people in hospitals with pneumonia, and they are finding positives. That’s not because all of a sudden in December and January we have this mutated virus that is very contagious. It’s because the virus has been circulating for months in Wuhan.”

WHO acknowledged that there are still many unknowns, as cases have been reported in five WHO regions in one month, and human-to-human transmission has occurred outside Wuhan and outside China.

“The committee believes that it is still possible to interrupt virus spread, provided that countries put in place strong measures to detect disease early, isolate and treat cases, trace contacts, and promote social distancing measures commensurate with the risk,” WHO stated.

The committee emphasized that the declaration of a PHEIC should “be seen in the spirit of support and appreciation for China, its people, and the actions China has taken on the frontlines of this outbreak, with transparency, and, it is to be hoped, with success. In line with the need for global solidarity, the committee felt that a global coordinated effort is needed to enhance preparedness in other regions of the world that may need additional support for that.”

Priority measures are rapid development of and access to potential vaccines, diagnostics, and antiviral medicines, which will be particularly necessary if the virus spreads to countries with few resources.

“It is expected that further international exportation of cases may appear in any country,” WHO stated. “Thus, all countries should be prepared for containment, including active surveillance, early detection, isolation and case management, contact tracing, and prevention of onward spread of 2019-nCoV infection, and to share full data with WHO.”


  1. World Health Organization. Statement on the second meeting of the International Health Regulations (2005) Emergency Committee regarding the outbreak of novel coronavirus (2019-nCoV), Jan. 30, 2019. Available at:
  2. Barton A. Update Wuhan coronavirus — 2019-nCoV Q&A #6: An evidence-based hypothesis. Science Speaks: Global ID News. Jan. 25, 2020. Available at:
  3. Huang C, Wang Y, Li X, et al. Clinical features in patients infected with the 2019 coronavirus in Wuhan, China. Lancet 2020; Jan 24. doi: 10.1016/S0140-6736(20)30183-5. [Epub ahead of print].