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Stories: John Pauk, M.D.

Going viral: A conversation about the science of COVID-19 with John Pauk, M.D., medical director for infectious disease

As Washington state inches toward reopening, questions remain about COVID-19, how it spreads and its effects on patients. We sat down—virtually—with John Pauk, M.D., our medical director for infectious disease, to find answers to some of the questions that have been keeping us up at night.

What we know and understand about this virus seems to change daily. Is this level of uncertainty normal?

No, it’s not normal. Even with other recent epidemics, like H1N1, we at least had a framework from other influenza viral strains with which to understand and predict transmission dynamics. A lot of the uncertainty related to this virus comes from the fact that it is new and without any directly comparable analogs. And some of the early predictions we made based on knowledge of MERS or SARS turned out to be inaccurate.  We’re having to make sense of it in the context of what we know about other respiratory viruses in general, but we don’t yet understand all of the variables related to modes of transmission.

With the constant stream of revelations about the virus, how do I separate the good-to-know from the need-to-know?

There are a lot of things we already know that will remain constant. This virus is primarily transmitted by respiratory droplets and fomites on contaminated surfaces, so how you protect yourself is going to remain the same. Physical distancing will continue to be important. Good hand hygiene will always be essential, because touching contaminated surfaces and subsequently touching our nose or eyes is an important mechanism for transmission. And masks will continue to be important.

Speaking of masks, there’s been a lot of debate about their benefits, particularly in public. Can you clear up why it’s important?

There is a fair amount of evidence showing that if someone with a respiratory virus wears a mask, that can markedly reduce the amount of infectious droplets going into the environment. A mask also protects the wearer from infectious droplets from entering their mouth and nose. However, the most compelling reason for wearing masks in public is that can stop infected people from spreading the disease. So even if someone does not care about their own safety, refusing to wear a mask in public may put others at risk.

We’ve stayed home for more than two months now. We’ve closed business and schools, stopped gathering in large groups and started wearing masks. Why haven’t we beaten this thing yet?

Well, there is still ongoing mixing of infected and noninfected individuals. Although limited, there is still ongoing social interaction. Essential workers still go into work. Patients cannot isolate themselves from others in their household completely in many situations. It is also true that people are still moving between different geographic regions. So even if we try to maintain control of transmission in Seattle, all it takes is for a few infected people traveling into our region for us to be back at our baseline. And it has been increasingly recognized that asymptomatic individuals can transmit the virus, so until we test much more broadly, we cannot start to effectively control transmission through contact tracing.

It sounds like you’re saying the only way to really beat this is with a vaccine.

Yes. Unfortunately, we can slow it down, but we are not going to eliminate it until we have a vaccine or develop widespread herd immunity. But the costs of allowing the virus to spread enough so that we have a large amount of population immunity are not acceptable. That’s why it will be so important for people to commit to changing their behavior around hand hygiene, physical distancing, and masking in the long run.

We've heard a lot about the fact that COVID-19 is caused by an RNA virus. What’s the difference between an RNA virus and a DNA virus?

All viruses transfer their genetic material to the host by either RNA or DNA nucleic acids. They basically insert this genetic material into the host cell’s machinery to produce more virus. RNA viruses tend to have more genetic variability and to change more over time. And DNA viruses tend to be more stable. So because RNA viruses may show faster evolutionary changes, they may develop more easily into strains that can be transmitted, thus causing an epidemic.

Will that tendency to mutate make it any more challenging to develop a vaccine?

With the flu—another example of an RNA virus—you have what’s called antigenic drift, which means the antigens that our antibodies attack change from season to season. So developers of a vaccine will probably have to look at what parts of the virus are more stable and less likely to change over time as targets.  At this point, it is not clear if there will be enough seasonal variability in SARS-COV2 to make this a complicating factor in vaccine development.

How might this experience change how we interact socially in the future? Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, has suggested that we never shake hands again.

In the short-term people may change many of their social behaviors, but by looking at different infection threats over time we see that people tend to eventually revert back to old patterns.  It is the proximity to a perceived threat that affects our behavior. As soon as people perceive that they are no longer in danger, people tend to go back to where we were before. I suspect, despite our better judgment, this will be the case once COVID-19 is no longer a threat.

What is more important is that we become better prepared—here at home and around the world—to respond to future pandemics. Once we are on the other side of this, hopefully the most important lesson we’ve learned is the importance of being prepared to deal with the next threat more effectively.

As of May 18, King County is requiring residents to wear face masks inside businesses and in crowded outdoor spaces. You can learn how to properly don and doff your personal face mask in our helpful video.