New Covid-19 Insights: Antibody Testing, Healthcare Disparities, and More

A conversation with immunologist Heather Zwickey, PhD

By Natural Medicine Journal

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This interview was recorded on April 13, 2020.

This update features information about recovery from Covid-19, antibody testing, how long the virus lives on surfaces, healthcare disparity that increases risk of death, and new information about air pollution and Covid-19. Heather Zwickey, PhD, is executive program chair and a professor at National University of Natural Medicine in Portland, OR. She also has previous training and experience with infectious diseases.

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Approximate listening time: 15 minutes

About the Expert

Heather Zwickey, PhD, earned a PhD in Immunology and Microbiology from the University of Colorado Health Sciences Center with a focus on infectious disease. Zwickey went on to complete a postdoctoral fellowship and teach medical school at Yale University. At the National University of Natural Medicine in Portland, OR, Zwickey launched the Helfgott Research Institute and established the School of Graduate Studies, developing programs in research, nutrition, and global health, among others. She currently leads an NIH funded clinical research training program. She teaches at many universities and speaks at conferences worldwide. At Helfgott Research Institute, Zwickey applies her immunology expertise to natural medicine, with specific interest in the gut-brain axis in neuroinflammation. 


Karolyn Gazella: On this Natural Medicine Journal Covid-19 Update, we'll be talking about recovering from Covid-19, antibody testing, and healthcare disparity in the wake of Covid-19.

Hello, I'm Karolyn Gazella, your host, and the publisher of the Natural Medicine Journal. My go-to expert on this topic continues to be highly respected integrative health researcher and immunologist, Dr Heather Zwickey, who is executive program chair and a professor at National University of Natural Medicine in Portland, Oregon. Dr Zwickey also has previous training and experience with infectious diseases. Dr Zwickey, thank you so much for joining me today.

Heather Zwickey, PhD: Thanks for having me back.

Gazella: Well, we've got a lot to cover, but before we dive into the interesting topic of antibody testing, as I mentioned on a previous episode, my niece, who is a nurse, got sick and tested positive. She's now out of the woods, and she's doing much better, thankfully, but she had a very difficult week that included nighttime fever spikes, severe pleurisy pain, loss of her sense of smell and taste. How much do we know when it comes to recovering from these various issues associated with Covid-19?

Zwickey: It's different in different individuals. For most people, it takes 7 to 14 days to get smell and taste back. It takes 7 to 14 days for most individuals to stop feeling that chest pain and that pleurisy pain. It can take longer for individuals who have the severe headaches. That can actually last for up to 21 days.

Gazella: Okay. It's amazing how it just varies and there's just spectrum with individual patients. I do have one more question before we dig into antibody testing. Is there any new information as to how long the virus can live on surfaces? I've been reading these reports that it's longer than originally thought, but these aren't from scientific journals, so I'm just curious if you have any new information on that.

Zwickey: You would think that this would be a really easy question to answer, but it's not. It's hard because it's dependent on the environment. We know that room temperature is different than heat and humidity is different than dry and smooth surfaces are different than rough surfaces, and it depends on how many viral particles you start with. Let's talk about the reports from the scientific journals. Keep in mind that these are going to be studies that are conducted in a laboratory setting, so they've controlled things, like room temperature and humidity and surfaces.

There was a study out of Lancet, which is a British medical journal, that showed that, at room temperature, in 65% humidity, the virus can stay on wood and cloth for about 2 days. However, on a surgical mask, it was still present 7 days later, just it had a slightly smaller inoculums, number of viral particles that were infectious, and at 4 degrees Celsius, which is 39 degrees Fahrenheit for those of us who don't do that math quick in our heads, the virus was stable for 14 days on smooth surfaces.

Then, the New England Journal of Medicine also has done a study. Well, they didn't do the study. The researchers were from the National Institute of Allergy and Infectious Disease, and they've reported that the virus is more stable on plastic and stainless steel than on copper and cardboard, and the longest stability that they have found is on plastic, which is 3 days, and that is at room temperature. If you have a house that's set at a colder temperature, it'll last longer.

The thing to remember with all these studies is that you start with a certain number of viral particles, and then they have what we call a half-life, and so you watch the decay. If you start with more viral particles, then they stick around longer because the half-life takes longer to destroy the same number of viral particles. It's a numbers game.

Gazella: It's all, once again, with this virus, it's kind of all over the board.

Zwickey: It is all over the board.

Gazella: Let's talk about antibody testing because, I have to tell you, I'm fascinated by this. In the case of Covid-19, how does the antibody test work? Take us through the process from when you get the antibodies to interpreting the results.

Zwickey: Sure. We know that antibodies are these proteins made by your immune system, and you start by making IgM, which kind of acts like a sponge and tries to neutralize as many viruses as possible. Then you make IgG because this is a viral infection. Remember, IgG sticks around for almost 6 weeks, and when you're making it an infection, typically you're making it by day 5 to 7 of infection, and so for the next 6 weeks, you'll have IgG in your bloodstream.

Now, the tests that are coming out to measure those antibodies are ELISA-based. ELISA is capital E-L-I-S-A. It stands for something. I never remember,* but the ELISA is a direct ELISA or an indirect ELISA, and in the direct ELISA, what you do is you take virus particles or the virus by protein, attach it to a surface. If we're doing it in a lab, we're going to attach it to a piece of plastic, like a plastic dish, but it can be attached to little strips of paper, if you think of pH paper. Then, you add the patient's blood, and if there are antibodies in the blood, they'll bind to the virus because the antibodies are specific for that spike protein. Then, we add a way to detect the patient's antibody. Usually, we do that with another antibody. This one is made in an animal that is able to detect either human IgM or human IgG. Remember, IgM came first and IgG came second. We can detect either one.

The second antibody that we add to this assay has an enzyme attached, which turns a color. If the secondary antibody binds, then a color appears. If the secondary antibody doesn't bind, then it means there was no antibody, there was no IgM or IgG to the virus in the blood, and then you get no color at all. We call it a colorimetric assay because we can tell how much antibody is there by how dark the color is, and because we can do it either in a plastic dish or on a little piece of paper, we can do it much quicker. The disadvantage is because this test is not measuring virus itself, it just tells us whether people were exposed, not whether they're currently shedding virus.

Gazella: This is done through blood, right? I think you mentioned that.

Zwickey: Yeah. We're just adding blood to the assay.

Gazella: Okay. That brings us to a couple of important questions. If the patient has antibodies, does that mean they are in fact free of the virus and are not contagious?

Zwickey: No. You can have antibodies and still be shedding for weeks. Because you start creating antibodies early in infection, usually IgM by day 4 and IgG by day 5 to 7, but you may still be in the midst of your infection for another week, and you could be shedding for another 2 weeks. Ideally, we would have the capability for testing simultaneously both virus and antibody. Then we would know that somebody was virus-free and still had protection.

Gazella: Right, but with the testing shortage for the Covid test, that might be a pipe dream at this point. From a clinical standpoint, does it help if you have antibodies and then you stay quarantined? Even though you have the antibodies, you stay shelter in place or stay quarantined for another couple of weeks and then you go out? Is that a possible strategy?

Zwickey: That is a possible strategy, and I think that's probably what we'll see happening in this country because we don't have enough tests to test everybody.

Gazella: Exactly. Now, here's the other big question. Do we know how long a person is immune from Covid-19 if they have the antibodies or if they're protected from future re-infection?

Zwickey: We don't know, and we likely won't know for a few years. There's some research out of China that suggests that there have been people who have been able to be reinfected, and we wouldn't expect this if they had an active immune response. However, we know people in the United States are producing antibody because we've been able to use patient serum to treat very sick patients, from patients who have recovered. We collect the antibodies in the serum from people who have recovered, and then that can be used to address really sick people, but the fact that people in China have been able to be reinfected suggest that there isn't an active immune response in those individuals, and we don't know why.

Gazella: We'll have to kind of keep an eye on that. Well, I'd like to change gears a little bit and talk about this healthcare disparity issue because I think it's so important to open up a conversation about this. There are populations that are at much higher risk of dying from Covid-19, and that is becoming evident. For example, here in New Mexico, where I live, we have special concerns for our Native American Indian populations, and in hotspots throughout the United States, we know for a fact that we're losing far more African Americans than we are Caucasian Americans. Now, you, Dr Zwickey, you're helping to educate and train future doctors. I'd like to get your take on this from a clinical perspective through your lens as an immunologist.

Zwickey: Sure. First of all, health disparities are a real phenomenon in this country and others. Initially, what we thought was that most health disparities were due to access of care or cultural competency of the providers and a lack of minority representation in the healthcare field. However, as time has progressed and we've done more research, we know that there is many other factors that are playing a role in health disparities, including income and education, whether people are living in poverty and whether they have a high school diploma or not. Interestingly, children's health is related to their parents' education. This is a phenomenon that is real, but it's not just those things because we know that income and education determine a complex variety of things, such as where people live, the characteristics of their neighborhood, their employment, and the types of jobs they have and the risks associated with those jobs, and even their beliefs about diseases.

For example, there are many people who may not have the disposable income for medical expenses, so they put off seeing a physician, and a lot of times, those people have underlying inflammation. When they do go into an infectious disease, they already have low-grade inflammation that is elevated when we have something like a pandemic. While that low-grade inflammation may not have been at the level to trigger them seeking out medical care, it is at the level to make their disease more severe than other people's.

Gazella: Now, there are a couple things that you mentioned that I want to expand upon because I think this-

Zwickey: Sure.

Gazella: ... concept of low-grade inflammation and where people live leads to a conversation about pollution. Now, my colleague and our Abstracts & Commentary editor of the Natural Medicine Journal, Dr Jacob Schor, brought to my attention an unpublished study showing that air pollution increases the risk of dying of Covid-19, which, again, increases risk for minorities who are living in highly populated, more-polluted areas of the country. Now, again, this is unpublished data, but it is getting some attention in the media. From a clinical standpoint, how should clinicians be advising their patients who live with air pollution? What's your take on this connection between air pollution and increased risk of dying of Covid-19?

Zwickey: Well, first of all, I think it's absolutely real. Remember that we have a microbiome in our lungs and in our gut, and our microbiome is very sensitive to air pollution, both in our lungs and our gut, and we know that the microbiome is producing less butyrate, which is healthy metabolite, if it's exposed to air pollution. We also know that macrophages in the lungs are able to ingest carbon particles, and they produce inflammatory cytokines as a result of that. This phenomenon is not a surprise for people who live in places with a lot of pollution.

What do you recommend to a patient? Well, if somebody has budget to buy an air filter for their bedrooms because we sleep overnight and we do our deep breathing when we're sleeping, I'd encourage them to do that, but, again, this is a great illustration of a health disparity. Often, people who live in these places don't have the money to buy air filters for every room. Then, what do you do if you can't afford air filters? Well, since we know the microbiome is involved, I'm always going to recommend eat more vegetables, eat more inulins and fructooligosaccharides and things that feed your healthy microbes because, really, we want those healthy microbes to start producing butyrate again.

Gazella: All that healthy diet is also going to be antiinflammatory as well.

Zwickey: Exactly.

Gazella: That kind of takes care of the low-grade inflammation. It's one of these complex topics that's so troubling. I'm glad that clinicians are talking about this because I think it needs to be something that we continue to talk about. This has been great information. Again, Dr Zwickey, thank you again joining me. For our listeners, if you'd like more information about Covid-19 and past interviews that I've done with Dr Zwickey, you can just go to Thanks again, Dr Zwickey. Thanks for listening, and stay safe, everyone.

*ELISA stands for enzyme-linked immunosorbent assay.

About the Author

Natural Medicine Journal is an electronic peer-reviewed journal and open access website dedicated to the field of integrative medicine.