Noted MUSC virologist helps separate COVID-19 fact from fiction

Catherine Mills
May 14, 2020
Dr. Paula Traktman, Dean of the College of Graduate Studies at the Medical University of South Carolina
Dr. Paula Traktman is a noted virologist and dean of the College of Graduate Studies at MUSC

As South Carolina enters the next phase in the COVID-19 crisis – reopening – many people have concerns about trying to integrate their pre-COVID-19 way of life with the new guidelines implemented by government and health officials. 

The public, too, might find it difficult to separate COVID-19 fact from fiction due to the constant barrage of rapidly evolving news headlines and the misinformation that too often spreads through social media. For instance, the Centers for Disease Control and Prevention (CDC) currently recommends that people adopt six feet of spacing between one another, but a recent study in the news reported that respiratory droplets and aerosols can travel up to 27 feet. 

Noted virologist Paula Traktman, Ph.D., dean of the College of Graduate Studies and Hirschmann Endowed Professor, was pleased to answer questions about and provide perspective on the virus at the heart of this crisis to help to clarify the science behind circulating headlines. 

“There are two guidelines to keep people safe. First, keep a social distance of six feet when out in public or at the supermarket.  Second, restrict people to no more than three or four in a room to reduce the exposure to any aerosols that may accumulate over time.”

-- Dr. Paula Traktman

In addition to her leadership role at MUSC, Traktman heads a research lab that is investigating vaccinia, a close relative of the smallpox virus. She has served on editorial boards of virology journals and on National Institutes of Health grant review panels. She also served as president of the American Society of Virology. Her active engagement in the virology community well qualifies her to provide insight on questions surrounding the COVID-19 virus.  

A recent article about respiratory pathogen emissions in the Journal of the American Medical Association  (JAMA) has been referenced in 451 news stories because it suggests that the virus can travel as far as 27 feet. That finding seems to contradict current CDC guidance that people maintain a “social distance” of six feet. What is your take on this? 

There is a difference between real-world transmission and transmission studies in the lab under a controlled setting. I have no doubt that there are conditions where explosive release, like a sneeze, can cause aerosols to go a long distance. However, I think all the data still strongly support that, in typical social situations, the virus will be largely in droplets that will go no more than six feet. 

There are two guidelines to keep people safe. First, keep a social distance of six feet when out in public or at the supermarket. That is really to stop you from transmitting or receiving larger droplets that could contain virus. Second, restrict people to no more than three or four in a room to reduce the exposure to any aerosols that may accumulate over time. I think the JAMA article is interesting, but I do not think it really addresses how we should be social distancing.  

Should people be wearing masks in public?

There is a lot of controversy with masks. We want to make sure N95 masks are available to the people who need them. Homemade masks are not going to be as efficient as an N95 mask, but N95s are in shortage and belong with the health care workers. 

“I am surprised by how few people have been wearing masks. I put on two masks to go into the grocery store the other day. There is no way I would be in a confined space with other people without a mask.”

-- Dr. Paula Traktman

A mask, even if it is homemade with a four-ply T-shirt, makes a big difference because it’s going to capture wet droplets and make it much more difficult for the virus to get through. Even if homemade masks cut transmission by two-thirds, that is a lot. 

I am surprised by how few people have been wearing masks. I put on two masks to go into the grocery store the other day. There is no way I would be in a confined space with other people without a mask. 

Why do some people who are positive for COVID-19 have symptoms while others do not? Are people who don’t have symptoms as infectious as those who do? 

That is an incredibly important question for public health. There is no doubt that health care workers who are testing and treating seriously ill people who are coughing and have fever are susceptible to being infected. We understand transmission in those cases. That does not explain the number of people who are being infected without being exposed to a seriously ill individual. As with all viral diseases, when people are sick at a hospital or at home, they are not going out to the beach or making a shopping trip to the grocery store and infecting lots of people in public. 

So, what is the spectrum of mild symptoms that make people think that they might be infectious, and do we understand that range of symptoms?

“We also know that people are infectious before they start showing symptoms. The virus is probably present in the nasal pharyngeal and back-of-throat area, and that’s not where symptoms are present in those with serious disease."

-- Dr. Paula Traktman

In truth, we do not have a great idea of how many people without symptoms are infected because we are not doing that kind of testing. In other words, if I had a mobile testing van where I could drive through a neighborhood and randomly test two people from every household, we’d have an idea of what percentage of people without symptoms are infected. We really don’t have a great number, but we are getting numbers from places that are doing some testing, and I would bet that we have more cases where people aren’t showing symptoms than cases where they are.   

We also know that people are infectious before they start showing symptoms. The virus is probably present in the nasal pharyngeal and back-of-throat area, and that’s not where symptoms are present in those with serious disease. Instead, their symptoms come from lung infection and the immune response, like the aches and fever you experience with the flu. It looks as if there are quite a lot of people who either show no symptoms or have only a mild illness. We do not yet know the variables that make the difference between somebody having mild fever for a few days and someone progressing to major infection. 

There had been much discussion in the press that African Americans are at greater risk for coronavirus? Why is this?

African Americans are at a greater risk for coronavirus, but not because they are African American. There’s not a racial predilection. Upper middle-class African Americans are not at greater risk for coronavirus. Low socioeconomic status, more than race, is a risk variable. People who live in large family groups in close proximity, are still working, have less access to health care and have preexisting conditions are at greater risk.

Many scientists, yourself included, have spoken out against theories that COVID-19 is man-made. Can you explain why this virus is not bioengineered?

RNA viruses, such as hepatitis C, HIV and influenza, have a very high error rate during replication of their genome and consequently change quite frequently. Unlike other RNA viruses, coronaviruses have implemented a mechanism to proofread their genome during replication, greatly reducing their error rate. This lower error rate makes it much easier to track changes in the virus’s genome. 

COVID-19 is very clearly derived from a bat coronavirus, and we know this because sequencing of it has been very thorough and done by many different groups. Bats are unusual because they act as a reservoir for tons and tons of viruses, but they do not get sick from them. While this is a bat virus, it has undergone specific changes. One of those changes is the ability of the viral spike proteins, which are the little knobs extending from the virus surface, to attach to ACE 2 receptors on target cells. 

“COVID-19 is very clearly derived from a bat coronavirus, and we know this because sequencing of it has been very thorough and done by many different groups.” -- Dr. Paula Traktman

The viruses that cause severe acute respiratory syndrome, or SARS, and Middle East respiratory syndrome, or MERS, originated in bats, but only SARS also invades the target cell through ACE 2 receptors. Even if scientists had wanted to design a coronavirus to target the ACE 2 receptor with high affinity, they would not have designed the spike in the way that it has evolved in SARS-CoV-2.  

 Also, when scientists are working to develop drugs for viruses, during the screening process they will use a clone of an infectious virus. The sequence for COVID-19 does not look like any of the clones that are used in the laboratory.

Finally, if bad actors were trying to create a virus with the intent of it being a major health threat, they would have done it in a different way. They would have chosen a virus that was more virulent and more often lethal. 

Many have speculated that the heat and humidity in the coming summer months could slow the spread of COVID-19. What are your thoughts on this?

There are certainly seasonal viruses, like seasonal coronavirus or seasonal flu, that don’t like warm climates for the same reasons they don’t like replicating in people who have a fever. We have no idea if that is going to happen with this virus. This virus spread in Australia during Australia’s peak summer months. The virus has also spread across Southeast Asia where it is warm. So, I think the jury is still out on that.

How can people protect themselves from infection as we move forward in reopening?

Avoiding groups is important. The greater the number of people in a group, the greater the chance that there is a person present in that group who is infected but not showing symptoms. Good hygiene – wash those hands, do not touch your face, wear a mask out in public – is very important. 

There’s a lot of work being done to develop a vaccine, and I hope we get one in a year. We still do not know for sure how effective a vaccine against coronavirus will be, as it’s still unknown whether we can establish long-term immunity against this virus. Screening for anti-viral drugs is also important. As soon as you test positive, you need to be able to have a drug that stops viral replication. 

Would you consider working toward developing anti-viral agents against COVID-19 here at MUSC?

MUSC would need a Biosafety Level 3 lab in order to work with COVID-19. If we had such a lab, there would be many of us in there combining virology and drug discovery to do the work. Unfortunately, right now we don’t have a Biosafety Level 3 lab.

About the Author

Catherine Mills
Catherine Mills is a Ph.D. student with an interest in medicinal chemistry and is working in Dr. Patrick Woster’s laboratory, which is focused on the design, synthesis, and biological evaluation of epigenetic modulators that serve as antitumor and anti-inflammatory agents in cancer and periodontal disease.

Keywords: COVID-19