That the U.S. and China are on different continents may give us the impression that we can stop the virus from entering through enhanced screening of people arriving at the airport. The novel coronavirus, like every other infectious disease, has an incubation period, the time between when one becomes infected to the time that one starts having symptoms.
The average incubation period, based on just 10 cases with definitely known exposure (among the first 425 confirmed cases in Wuhan) averaged 5.2 days. The upper limit of this guesstimate is 12.5 days. An individual traveling during the incubation period does not feel ill, and airport screeners would find that his temperature is normal.
Furthermore, the signs and symptoms of the novel coronavirus are nonspecific. The first 41 patients, had fever (98%), dry cough (76%), and shortness of breath (55%). Any run of the mill pneumonia or severe influenza-like illness can cause fever, cough, and shortness of breath.
Identifying the patient with novel coronavirus will require close attention to the places that a traveler has been.
The likelihood that those infected with the virus will come to Hawaii increases with the sheer number of infected people there are.
The Chinese authorities imposed a quarantine on Wuhan, the city at the center of the epidemic, on Jan. 23, on the eve of the Lunar New Year holiday, scheduled for Jan. 24-30. The mayor of Wuhan noted that 5 million people had already left Wuhan before quarantine was imposed. Migrant workers, with longer and more difficult journeys to their home provinces, had left early.
There are already hundreds of confirmed cases in China’s international hub cities of Beijing, Shanghai, Chongqing, and Guangzhou. In these megalopolises, person-to-person transmission is occurring among many who don’t know yet that they are infected.
By making it illegal for all residents of cordoned off areas to leave, quarantine penalizes unexposed, uninfected people, i.e., susceptible individuals. Quarantine promotes defiance of authority. If planes, trains, and buses are suspended, people will escape through back roads.
Moreover, for those who are exposed or infected, quarantine incentivizes hiding signs and symptoms of illness. Humane public health measures must encourage access to health care. Nonetheless, quarantines are essential and necessary in all epidemics but need to be fine-tuned as more information is gathered regarding incubation times and which individuals are most at risk.
The quarantine of American evacuees from Wuhan is justified as a measure to slow the entry of the novel coronavirus into the U.S. Airport screening is necessary because some who try to enter the US will be driven by the intent to obtain medical attention. Some infected individuals may try to get past the screening by taking fever-reducer such as acetaminophen or ibuprofen, knowing that if they are later identified to have signs and symptoms, they will get treatment.
A Potential Bioevent Disaster
In the end, how fearful should we be about this new virus? Keep in mind that it was the sickest people who first came to the attention of the health workers in Wuhan. They were the ones who needed to be hospitalized, placed on oxygen, and cared for in the ICU. Of those first 41 patients, six died, which calculates out to a 15% mortality.
But in the subsequent days less sick people were tested and found to have the novel coronavirus, too. Thus, of the first 835 patients, 25 died, i.e., a 3% mortality. The numbers are increasing day by day, so you can calculate the mortality rate yourself from today’s headlines. Take the number of deaths and divide by the number of confirmed cases. (Admittedly, some of the confirmed cases are still sick and could still die.) In recent days, this calculation yields a 2% mortality. As more people with mild symptoms or even no symptoms at all are tested, we may find that they have been infected, too.
A 2% mortality is nothing to sneeze at, though. The mortality rate of most influenza pandemics is <0.1%. The Great Influenza of 1918-1919 had a less than 2.5% mortality, and between 50 to 100 million people died globally.
China’s lack of basic public health surveillance in wet markets and animals was responsible for SARS in 2003 and the current coronavirus epidemic. Heeding each and every public health requirement, no matter how unpopular or personally inconvenient, will once again win the battle.
Nothing erases your responsibility to others. Yes, we are faced with a bioevent disaster. We must approach this rationally, utilizing population-based public health principles. Stay safe while our scientist friends come up with a vaccine.
Seiji Yamada is a family physician practicing and teaching in Hawaii.
Frederick M. Burkle, Jr. is Professor (Ret.), Senior Fellow & Scientist
Harvard Humanitarian Initiative, Harvard University & T.H. Chan School of Public Health, Senior International Public Policy Scholar Woodrow Wilson International Center for Scholars, Washington, DC nstitute of Medicine, National Academy of Sciences, elected ’07, Captain, MC, USNR (Ret.).
This article first appeared in the Honolulu Civil Beat.