To understand the impact of the COVID-19 outbreak in China and its spread to other parts of the world, GLG recently sat down with Dr. Stephen S. Morse, Professor of Epidemiology at the Mailman School of Public Health of Columbia University. In 2014, the United States Secretary of the Department of Health and Human Services appointed him to the National Science Advisory Board for Biosecurity. Since 2016, Dr. Morse has been a member of a World Health Organization expert group on pandemic influenza preparedness planning in the Eastern Mediterranean region. His comments on the COVID-19, edited for space, appear below.
GLG: Dr. Morse, based on the latest figures, how would you currently classify the epidemic?
Dr. Morse: In a sense, there are two epidemics. The one in China started first and is continuing to evolve fairly quickly. Globally, we’re seeing a much smaller epidemic that hopefully will remain small, due in large part to the public health response in each affected country.
GLG: How close are we to seeing the rate of infection peaking?
Dr. Morse: I’m not sure China is at the peak because the incidence of the disease continues to increase. In the last few weeks, it’s increased exponentially, almost doubling every day. Since this infection has an incubation period of between two and about 14 days, we’ll be able to see a peak fairly rapidly once it occurs. Similarly, if it starts to decline, the drop likely will become apparent within about a week or two. What we’re looking for is an inflection point where we see the curve going down and remaining down for at least a couple of incubation periods.
GLG: Based on current evidence, what’s your expectation for the mortality rate, the infection rate, and the speed of spread?
Dr. Morse: We have limited data on that since almost all the data are coming from China. We have little information from the other cases because there are so few of them. It would appear so far that the case fatality rate is roughly 2%. That rate has been dropping slightly, which is expected, because early on you tend to have an overrepresentation of the sickest people, which increases the fatality rate. At 2%, the rate is not Ebola-like, but it’s higher than the rate for the flu, so it’s not entirely trivial.
As far as the infection rate is concerned, we know that there must be milder cases that are not being noticed, or not being reported simply because the serious cases go to the hospital and milder cases may not come to medical attention. I suspect that there are probably more infections and that the true fatality rate will be much lower than it is today.
The rate of spread is quite rapid in China, but in other places it’s been impeded by rapid and strenuous public health efforts to control it, which is encouraging. After years of watching similar situations, often in frustration, it’s really quite something to see the international community and national public health authorities go into action fairly quickly.
GLG: It seems that COVID-19 is spreading much faster, but is perhaps less virulent than the SARS virus, which caused close to 800 deaths worldwide. What are some of the similarities between COVID-19 and past outbreaks, such as SARS or MERS?
Dr. Morse: They’re all known as coronaviruses since their appearance under the electron microscope is sort of crown-like. COVID-19 and SARS are closely related and are on the same branch of the family tree. They’re sort of cousins. The main difference is that SARS and MERS were largely driven by healthcare-associated infections. In other words, most of the infections occurred in hospital or clinical settings, and many of the people infected were healthcare workers or hospital patients. Usually, those illnesses resulted from what we would call aerosol-generating events, in which a healthcare worker might accidentally inhale something that contained the virus. This particular coronavirus is spreading human to human; with SARS and MERS there was very little person-to-person transmission, making this a completely different sort of dynamic and explaining why it has spread so quickly – more like influenza.
GLG: Are the border closures, flight restrictions, quarantine measures, and other steps nations have taken appropriate given what we know about the disease?
Dr. Morse: Since this disease does spread readily, there is a case for imposing travel restrictions. Usually, travel restrictions only encourage people to find ingenious ways to get around them and for people not to report if they have a problem. I think at some point as we learn more about COVID-19 and get it under better control, we’ll probably see some loosening of restrictions, but we should maintain a high level of vigilance and disease control, especially at points of entry.
GLC: What about the possibility of a vaccine?
Dr. Morse: There are a couple of vaccine candidates now in the early stages of testing. After candidates are identified, of course the harder part is doing the preclinical studies on animals to determine if the vaccines elicit some indication of an immune response. That’s not quite equating with humans, but it shows you some promise. The next step is testing healthy human volunteers, which I’m speculating could be done perhaps as early as spring. The harder part is then demonstrating effectiveness. The FDA and other agencies may be willing to fast-track a vaccine and allow it to be used if there are no clear adverse reactions and it looks safe. There may not be time to test it for effectiveness. Even so, that process would probably take several months at best.
Aside from approval, one of the other big elements is production. How quickly can it be ramped up? As there are only a limited a number of vaccine companies in the world and limited vaccine capacity, ramping up production probably will be the most arduous part of the solution. So if we’re looking for a vaccine to save us, we probably will have to wait three months at the very least and more likely six months or longer.
There also are therapeutics now being tested. One drug that is being tried with coronaviruses, Remdesivir, which is a product of Gilead Labs, must be used intravenously. In laboratory tests, it seems to have good effectiveness against coronaviruses and is being tried now. There’s another experimental drug that’s available in pill form, but it’s just in the early development stages and probably will take at least another six months to come out.
GLG: Outside of laboratories, we no longer see cases of SARS. Do you expect this outbreak to be similar and become a one-off event or will it become a semi-permanent epidemiological feature?
Dr. Morse: There are many viruses out in the world with properties like SARS and probably similar to COVID-19. Over the next several weeks, we will have to see if this one establishes itself in the human population the way flu has. But even if it turns out to be a one-off, I believe we are going to see something very much like it in the future. Hopefully, from this experience, we’ll learn to take these threats more seriously from the beginning.
About Stephen S. Morse
Dr. Stephen S. Morse is currently Professor of Epidemiology at Columbia University’s Mailman School of Public Health. He was also Global Co-Director of the “PREDICT” project (of the USAID-funded “Emerging Pandemic Threats” program), intended to strengthen global surveillance of infectious disease threats. Prior to this, Dr. Morse was founding Director of the University’s Center for Public Health Preparedness. Dr. Morse’s book “Emerging Viruses,” published in 1993, was selected by American Scientist as one of “The 100 Top Science Books of the 20th Century.” His second book, “The Evolutionary Biology of Viruses,” was published in 1994.
This article is adapted from the GLG Teleconference Assessing the COVID-19 Outbreak. If you would like access to this teleconference or would like to speak with Dr. Morse, or any of our more than 700,000 experts, contact us.
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