Countries around the world are actively searching for cases of the new coronavirus in an effort to stop its spread around the world. But if they can’t contain the virus, public health officials may need to start fighting a different battle. Right now, countries are relying on measures like quarantine and isolation and hoping that they’re enough to beat back the outbreak. If those don’t succeed, the virus might transition from being the cause of a temporary epidemic outbreak to one that causes a new circulating disease.
Because we’re still learning about the severity of the virus, the implications of that switch are still hazy. But the progression will be driven by social and political tolerance for the new illness almost as much as it is by biology.
“We’re going through the panic phase,” says Graham Medley, director of the Centre for the Mathematical Modelling of Infectious Diseases at the London School of Hygiene and Tropical Medicine. “Governments don’t know what to do, people don’t know how to react. When we understand the risks, reactions will change.”
Right now, China is facing a coronavirus epidemic: a rapid spread of the illness affecting a large group of people in a short amount of time. If the epidemic continues to spread dramatically into other countries, it could become a pandemic (and some experts say it already is). If interventions still don’t stop the spread of the virus, it could shift from being an epidemic or pandemic and become endemic. There’s no single definition of what counts as an endemic disease. For epidemiologists, diseases become endemic when they’re continuously, predictably present in the human population. Politicians, though, might call a disease endemic when it’s well-understood enough that it stops being an unknown threat for the government, Medley says.
“For most people, the difference between epidemic disease and endemic disease is that the risks are unknown for an epidemic disease”
“For most people, the difference between epidemic disease and endemic disease is that the risks are unknown for an epidemic disease. People fear contracting this novel coronavirus because they don’t know what it’s going to do,” he says. “The definition is really based on how the risks are perceived by individuals and by governments.”
Take influenza, which technically causes an epidemic outbreak each year but doesn’t trigger the same kind of public health mobilization we’re seeing with the coronavirus. Every time we have a new epidemic, Medley notes, people compare it to the flu and say that the flu is infecting and killing far more people.
“We don’t have this kind of government response to the flu every year. The US doesn’t say, influenza is going to be introduced from Vietnam, so let’s stop all flights from there,” he says. But that’s because public health officials and governments know the risks of the flu. They can predict its patterns and focus on mitigating its impact through education and vaccines.
People are much more comfortable with something well-understood and predictable, says Erin Sorrell, assistant research professor in the department of microbiology and immunology at Georgetown University. “People tolerate the risk of exposure to seasonal flu,” she says. “We’re comparing a risk tolerance of something new and novel and not well understood, versus something we see year after year.”
Public health experts still don’t know how dangerous the new coronavirus can be, and their response is elevated because of that uncertainty. In addition, because the virus is new, there’s still an opportunity to stop it from spreading through the population. That’s what happened with SARS, which was contained in 2004. Overall, endemic diseases — even though they seem less scary and come with less uncertainty — cause more illness and death than epidemic outbreaks like SARS. But they’re much harder to stop.
“The reason we react so aggressively to novel diseases is that we have a chance to contain transmission to the source of an outbreak, and prevent it from getting larger,” Sorrell says.
“The reason we react so aggressively to novel diseases is that we have a chance to contain transmission to the source of an outbreak, and prevent it from getting larger”
Experts at the World Health Organization (WHO) say that it’s not too late to stop the spread of the new coronavirus. Other infectious disease specialists, though, aren’t so sure. “The more we learn about it, the greater the possibility is that transmission will not be able to be controlled with public health measures,” Allison McGeer, a Toronto-based infectious disease specialist, told Stat News.
The Centers for Disease Control and Prevention (CDC) is preparing for wider circulation of the virus around the world and in the US, said Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases at the agency, in a press call this week. “We do believe we have a window of opportunity now to prepare the US in case there is a broader spread of this outside of China, and a broader spread in the US,” she said.
Sorrell thinks we’ll know within the next few weeks if the new coronavirus can be contained. If it looks like it won’t be, public health efforts around the world will likely slow their active searches for new cases and focus on efforts to treat and mitigate the impacts of the virus — similarly to how they manage the flu. “Those efforts are ongoing, but they’ll be ramped up,” she says. There will be more research into antivirals to treat people who are infected with the virus and continued investment into the development of vaccines. “We’re not starting from scratch.”
If the new coronavirus can’t be effectively contained, it might be added to the list of diseases that people in the general population are regularly exposed to. There are already a handful of coronaviruses that circulate, causing mild colds and respiratory symptoms. “Potentially, this could join that group,” Medley says. It also might turn into something that crops up seasonally, like the flu, circulating widely during a few months and they dying back down.
The transition from novel, emerging virus to sustained threat has happened before — most recently, with HIV, which offers the closest example of what could happen with the coronavirus, Sorrell says. “It started as an outbreak of an animal virus spilling into humans,” she said. “That had an ability to cause local, regional, and then global outbreaks, leading to a pandemic. That led to investments in research about infection control, and the routes of transmission. We were able to contain the outbreak, but it became a pathogen that was able to sustain itself in the population.”
HIV is still classified as a global pandemic. But people adjusted, experts did the work to understand the best ways to minimize the risks of the virus, and there isn’t constant, fearful reporting about each new case of illness. It’s hard to say what the process might look like for the coronavirus, but as we gather more information about the risk of this new pathogen, individuals and governmental perceptions and tolerance would settle to a new baseline.
In an ideal situation, public health containment efforts will be enough to halt the spread of the virus. But if they aren’t, ongoing research efforts will most likely drive an acclimation to a new normal.
“If this becomes a pathogen sustained in the population, we’ll understand it better because it’s been around,” Sorrell says. “Epidemics become increasingly tolerated.”