Empty classrooms, shuttered restaurants and hospitals bursting with patients. That was the scene in Mexico City in 2009 when a new strain of flu swept across much of the country and spread around the world.
Just 11 years after the swine flu outbreak, which infected more than 60 million people in the US alone and took as many as half a million lives worldwide, the new coronavirus is threatening to spark another global epidemic.
Health officials are trying to contain the virus that causes Covid-19, a pneumonia-like illness that can be severe in a minority of patients and spread from others who look healthy. Now, researchers and disease trackers are teetering on the brink of calling it a pandemic, a crisis that will likely affect the entire world.
“We’re on the knife-edge,” said William Schaffner, a Vanderbilt University infectious disease specialist who’s been through the Asian flu, Hong Kong and swine flu pandemics.
Two months after emerging in China’s Hubei province, the coronavirus has hit at least four continents, with rising case counts and huge responses in Iran, South Korea, Italy and Japan. More than 80,000 cases have been reported, including some 2,800 deaths. Authorities in the US and Thailand are warning about wider outbreaks in their countries.
Yet most of the cases and clusters are traceable, according to the World Health Organization, meaning that for the most part community spread outside China is rare. Questions over the nature of the virus underscore WHO’s reluctance to call the outbreak a pandemic just yet, especially while there are early signs of slowed or stopped transmission in some countries.
A pandemic doesn’t have a formal numerical definition, said Schaffner, who has advised the US Centers for Disease Control and Prevention on infections. It’s an epidemic that becomes global, spreading in multiple countries. In most cases, measures to contain the epidemic in one region or country have failed, and the goal switches to mitigation — trying to ease the pain.
The distinction may not be necessary, according to Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases.
“The situation is getting worse; all you have to do is look at the numbers,” he said. “If the trend continues the way we’re seeing now, we’re going to have a problem. Whatever you call it, it’s not good.”
But the eight-letter word resonates with state and local health departments, hospitals, clinics and nursing homes, Schaffner said. Many of them have pandemic plans, developed and refined after earlier outbreaks, that will need to be dusted off, reviewed and implemented.
The reasons for calling this outbreak a pandemic now are many, according to Tom Frieden, a former CDC director and New York City health commissioner. Researchers can’t trace all the links between outbreaks in different nations; the spread in hospitals and families shows the virus is quite transmissible; some countries that haven’t reported cases probably have them; and simple calculations suggest the tallies of travelers with the disease are probably just a fraction of the real number.
“A pandemic is inevitable and we should call it what it is,” Frieden said. “What’s not inevitable is that it will be severe.”
Measures as simple as frequent hand-washing can help prevent the spread of the virus, public health experts say. Travel restrictions like those implemented in China have slowed its global spread, but probably won’t stop it, Fauci said.
People in the US should prepare for disruptions to daily life, warned Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases. In the event of a pandemic, schools may consider dividing classes into smaller groups or even shutting down, she said. Businesses will have to consider more telecommuting, and communities and cities may have to cancel mass gatherings.
The WHO has already declared the outbreak an international public health emergency. The situation may be more difficult to define as a pandemic, according to Michael Ryan, executive director of WHO’s emergencies program. Most pandemics are caused by flu, and the transmission of coronavirus needs to be studied further, he said. While new cases are falling in China, the possibility of a global outbreak is real, he said.
“It is time to do everything you would do in preparing for a pandemic,” he said in a press conference. “We’re still trying to avoid that eventuality and countries are having success in doing that. Let’s focus on what we can do.”
The coronavirus outbreak looks nothing like the 1918 flu that killed an estimated 50 million people worldwide. The pandemics of Asian flu of 1956-1958 and Hong Kong flu in 1968 are each estimated to have killed from 1 million to 4 million people.
Fortunately, unlike most flu strains, the new virus seems to leave children relatively unscathed, Schaffner said. That suggests fewer scenes like one he witnessed in the swine flu outbreak, when a five-year-old child died at Vanderbilt after being sent home from two other emergency rooms, he recalled.
Treatments for flu have improved since then, and doctors are already testing antivirals and vaccines against the coronavirus. Yet other signs of a pandemic may still come, such as shortages of hospital beds and patients waiting in hallways waiting for attention, he said.
“We’re at the edge of the cliff,” Schaffner said. “We’re in a more precarious position now than we were one week ago, and I see this week as determining what’s going to happen.”