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What We've Learned About Coronavirus

Infectious disease experts on the spread, the science and the scenarios for the virus

Dr. Jonathan Quick, Dr. Sallie Permar and Dr. Linfa Wang
Infectious disease experts Drs. Jonathan Quick, Sallie Permar and Linfa Wang

Three Duke infectious disease experts talked with the media Tuesday to discuss the origins and spread of COVID-19 and the global and U.S. response. Duke plans a series of briefings on the way the novel coronavirus is affecting the world.

Below are highlights from the briefing:

On the Wuhan Meat Market at the Epicenter of the Outbreak

Linfa Wang: “Without any doubt that market played an amplification role, but epidemiologically we knew there were cases in early December (that) had no link to the market, and never went to the market, earlier than the market amplification. … There’s a high chance the virus is not from Wuhan because central Wuhan is not well known for wildlife. Wildlife usually comes from southern China or is legally or illegally imported from neighboring countries in southeast Asia.”


On Similarities With SARS

Linfa Wang: “These two events are almost a replica, 17 years apart. The viruses, we now know, are 80 percent identical. The difference is, unfortunately, that COVID-19 is more transmissible: We identified the genome within three weeks of the outbreak, but for SARS that was five months. That means we have a molecule attached that can confirm cases rather than (leaving them as) suspected cases, whereas for SARS we could not do that until five months later. And yet, the total number of infected persons and countries affected by COVID-19 is much greater.”


On Seasonal Scenarios for the Virus

Jonathan Quick: “One is that it’s like the SARS virus in 2003, which within a matter of weeks got to 27 countries but in six months, it was gone and never returned. That’s the best-case scenario. … The second scenario would be more like the 1918 flu pandemic, where it gets quiet in the summer and then was back again in the fall. And the third scenario is that it actually doesn’t have much of a seasonal effect, it just keeps on moving along until we get a vaccine.”


On Why Children Seem Less Affected

Sallie Permar: “We'll have to keep following to know whether that's through a lack of testing, or whether it’s true that they are protected from even acquiring the infection. But there's a number of reasons this could be playing out. One is just a younger immune system that may be able to better respond to a new virus infection. … Another possibility that's been raised is this idea of cross-protective, preexisting immunity – that maybe because children generally do carry more infections and pass them around to each other in schools, that possibly some innate or cellular immune response does contribute to some protection.

“And then finally, maybe it doesn't have anything to do with the immune system but there's something different about those lung cells in a child, versus an adult, that protects the child. These are all areas to continue to study that could be harnessed for potential treatments and vaccine approaches.”


On the Effect Upon Health Care Services

Jonathan Quick: “There are two dynamics that happen with health services in outbreaks. One is that they get overwhelmed by people coming in, and that gets in the way of keeping regular services going because we sometimes lose as many people from disrupted services as we lose from the epidemic. … The second thing that happens is it turns the health facility into a transmission center. So one of the things that health services in each city and state need to do here is to get uniform messages and calling services so people can find out when to come in and when not to come in.”


On Why Recommendations Matter

Sallie Permar: “It’s so important for the population to really take heed of social distancing, canceling travel, canceling large events, because how we behave in the next few months will have a major impact on how many cases are occurring at one time. And if we can flatten the curve and spread out the number of cases over a number of months,  I think our health system will be able to continue to provide excellent services.”


On the Readiness of the Research Community

Sallie Permar: “One thing that has become clear since 17 years ago when SARS was a major epidemic, is that there was an opportunity there for us to put more work into developing potential vaccines for things related to SARS, other coronaviruses. And when you look across the landscape, there are relatively few labs that were funded to continue to work on that. … Really, the model does need to change, so that we are able to not only just have the (genome) sequence in hand quickly, but also have ready-made vaccine platforms that can develop within a number of months, and go into safety testing quickly after that.”


On Organizational Preparedness

Jonathan Quick: “Businesses should have a pandemic business continuity plan, but the single biggest weakness is they’ve not practiced their plans. … I would urge hospitals and businesses to rehearse those plans, to really go through it so it’s not just a plan on a shelf.”



Dr. Jonathan Quick is an adjunct professor of global health at Duke Global Health Institute.

Dr. Sallie Permar is a professor of pediatric infectious disease, immunology and molecular genetics at Duke School of Medicine.

Dr. Linfa Wang is the director of the Programme in Emerging Infectious Diseases at Duke-NUS Medical School in Singapore.