Asymptomatic on the Front Line? You May Have COVID Antibodies

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This transcript has been edited for clarity.

Robert D. Glatter, MD: Hi. I'm Dr Robert Glatter, medical advisor for Medscape Emergency Medicine. I want to welcome Dr Craig Spencer, assistant professor of emergency medicine and director of global health at Columbia University. Welcome, Craig. It's a pleasure to have you with us.

Craig A. Spencer, MD, MPH: It's great to be here. Thanks for having me.

Glatter: Today we're going to talk about a CDC study from early September about the prevalence of antibodies to SARS-CoV-2 among healthcare workers during the months of April to June in 13 academic medical centers from 12 states in the United States. It's part of the Influenza Vaccine Effectiveness in the Critically Ill (IVY) Network that looks at influenza prevention.

The study has some important findings regarding the prevalence of antibodies to SARS-CoV-2 among healthcare workers, as well as the percentage of healthcare workers who are asymptomatic but had antibodies to the virus.

Craig, I'll let you jump in here. Please talk about the study, the design, and what we should be taking away from this.

Spencer: Sure. I was glad to see this study, and I know that since then, there have been a couple other studies looking at similar issues. I appreciated that they had a mix of hospitals and providers within the hospital (eg, ICU doctors, nurses, people in the emergency room).

I also appreciated that they looked at hospitals from many different zones, including places that had higher rates of infection or higher rates of SARS-CoV-2 in their community (eg, Montefiore) vs places that may have had less (eg, Wake Forest University Baptist Medical Center, Oregon Health and Sciences University Hospital) in comparison.

As someone who was working on the front lines in March and April, I was concerned certainly about my own health and about the health of my colleagues. Having worked in an infectious disease outbreak in 2014 and Ebola, I knew how important it was to be physically and mentally prepared, but also the impact that having an infection within your ranks could have on the morale of your group.

Anyone in New York City, or anywhere that the virus hit hard, likely had friends or colleagues that were infected. I certainly had colleagues of mine that passed away from this virus.

This is a really important study. I'm glad that we have information to show that many of us on the front line, even if we were using personal protective equipment (PPE) and taking all the right precautions, are still in a risky business. I think that's worth highlighting.

Glatter: Looking at this study, where there were PPE shortages, there were higher levels of antibodies. That really speaks to itself. There was 10% or higher prevalence within that group testing positive in eight of the 13 centers.

Spencer: As someone who's gone through this before, I was wearing a mask starting in early February, because I was concerned that we were going to have cases. Here in New York City, we went from having a trickle of cases within the span of 1-2 weeks in the emergency rooms to being dominated by COVID cases.

It was really important for all of us early on to make sure we were following protocols and wearing the right masks. As you pointed out, there are many hospitals or many healthcare systems that did not have access to sufficient PPE. There was changing guidance almost on a daily basis around when you needed to have an N95, when you need to wear a surgical mask, and what other face covering during which procedures. That was super-confusing for everyone, including myself, who's gone through this before.

I don't think it's too surprising that there appears to be a correlation between a lack of PPE and a higher likelihood of showing antibodies, even in asymptomatic healthcare workers.

We know that the best way to protect yourself is with the right protection — masks, gloves, eye protection, proper handwashing — and being in an environment where all of those procedures are respected, and you have good guidance. Quite frankly, not everyone and not everywhere had that really early on, and we got hit pretty hard.

Glatter: That point is so well taken. Another point that comes to my mind is looking at the number or at the communities themselves in terms of the prevalence of antibodies; it correlated with the hospital within the studies. In other words, if there was a high level of antibodies at one academic center, it correlated with the community.

Are healthcare workers converting from activities outside the hospital beyond just working in the hospital itself? In other words, what they do beyond their time when they work?

Spencer: That's a really good question. I don't know that we have enough of that evidence. It's not surprising to me to see that the in-hospital provider numbers correlate well with the community. If there's a lot of virus in the community, that makes it more likely that the providers themselves are going to be exposed.

I can speak on the New York experience. It's unlikely that any of the providers were exposed outside of our clinical work really early on (especially in March, April, and even through May), because so much was shut down. We really were just going to work and coming back home, trying to keep our families safe and isolated.

I suspect that there's likely some contribution from community infection as opposed to healthcare infection, especially if people are being really good about their PPE and their protocols. As you're aware, and as I think any provider is aware, before this, how often did we wear an N95? How often did we really think seriously about our PPE and how it protected us?

We're lucky that in the United States, it's relatively rare that we get TB cases or other things that spread like SARS-CoV-2. As opposed to many other places I work in around the world (West Africa, East Africa, and Southeast Asia), where people are more used to wearing PPE and wearing it well, I do think that there was a learning curve pretty early on. I know that many of my friends were infected within the first few weeks.

Even having enough PPE is not a guarantee that you're going to be prevented from getting an infection, and I think that might be reflected as well in some of these numbers.

PCR vs Rapid Antigen Testing

Glatter: Moving on to testing. Many centers are starting to test their workers routinely, but others are not, which plays into the narrative of rapid testing and whether that's valuable. In other words, PCR vs rapid antigen testing, and how we can integrate this into protocols.

Now, again, talking about infectiousness vs infection, we can focus on that. Working in a hospital setting, we're at high risk, high exposure. There's no low prevalence of the virus. Whether we use one test or another to monitor ourselves is key.

Spencer: Yeah, there are a couple of things to unpack there. There was a study a couple of weeks ago in JAMA from Brigham showing that the nosocomial infection rate was quite low.

If you have dedicated procedures and protocols for protecting patients who were not COVID positive when they came in to the hospital, the likelihood that they would get infected when they were inside was quite low. I think that speaks to having protocols and procedures in place, and good PPE guidance.

Now, in terms of testing our providers, you're right — we have many more options than we did early on in this pandemic. I remember so many of my colleagues who had symptoms and tried to get tested at hospitals all throughout the city. For so many of them, it was nearly impossible.

It's become much easier now. Access to PCR tests, especially at bigger academic healthcare centers or medical centers, has increased substantially. Many communities have better access to testing than even just a few months ago, with faster turnaround.

The question is, what role do we want these tests to play? If we have someone that we're concerned may be sick, either a patient or a provider, and we need a yes or no answer, I think the PCR is still the standard of care.

For others, in terms of screening, antigen tests will certainly have a role. We do know that they may have a high false-negative rate and they may be better at picking up people who are infectious as opposed to infected but unlikely to spread the disease.

I think it all depends on what we're trying to measure and what type of patients or providers. When we look at the serology results, I think it's important for us to retrospectively look back to see how well our PPE worked in places that had it.

It's also nice to know that a good chunk of the people who did have positive serology for COVID antibodies were asymptomatic, but that may also reflect the likelihood that maybe our workforce in the emergency department or in the ICU skews to a younger age, with a bunch of residents and younger healthcare professionals.

Glatter: The average age in this study was young (about 36) and there were more nurses (44%) vs physicians, NPs, and others (about 28%), so a little bit more weighted toward nurses. Do you think that really has any bearing on what we're finding in this study?

Spencer: It's hard to say. I remember talking about this really early on because many people who had the most severe and negative outcomes, either really severe illness or death, throughout the city were nurses. There was speculation, of course, that they're having a lot closer contact with patients much more frequently. Physicians were doing the aerosol-generating procedures (ie, intubation and so on), so I'm not really all that surprised.

Nurses are amazing for a billion reasons, but I think everything that they've done throughout this pandemic has just really highlighted how much we need them. They're such a huge support and part of the backbone in the emergency department in the hospital and in the ICU. I'm not surprised.

Key Takeaways

Glatter: If you wanted to give us a few takeaways from this study, what would they be? What is the take-home message for the audience?

Spencer: We need PPE. We need enough of it. We need to make sure that whenever we go to work, we're able to access the N95s, the gloves, and the things that we need to stay safe.

Even if we have that, we need to make sure that we're using them well. One thing that I think is helpful, and I've used before in other contexts, is having a PPE buddy. Whoever you're working with on a shift, even if you think your N95 and your goggles are on correctly, often they're not and it's leaving you vulnerable. Have a PPE buddy, someone who can interact with you pretty frequently during your shift, who will let you know if your things look right, if your mask is on okay, if there are holes, or if it's visibly soiled.

The other thing I take away from this is that our work is indeed dangerous. We may have the protection we need, but I think we all need to be quite smart on how we manage this to make sure that we stay safe. We need to continue to monitor our own symptoms so that we don't infect our patients or other colleagues while we're at work.

The last thing that I take away from this is that the importance of testing is huge. We need access to all types of testing throughout this pandemic. It's not over. It won't be over for months even after we have a vaccine. All of those different types of tests — the antigen tests, the PCR tests, and the serology tests — are going to play a unique role in how we get this pandemic under control and how we get through it safely as providers, as patients, and as a general community.

Glatter: That's great. I really appreciate your time. This has been incredibly helpful. Thank you.

Spencer: Absolutely. Thank you.

Robert D. Glatter, MD, is an attending physician at Lenox Hill Hospital in New York City and assistant professor of emergency medicine at Zucker School of Medicine at Hofstra/Northwell in Hempstead, New York. He is an editorial advisor and hosts the Hot Topics in EM series on Medscape. He is also a medical contributor for Forbes.

Craig A. Spencer, MD, MPH, is an assistant professor of emergency medicine and the director of Global Health in Emergency Medicine at NewYork-Presbyterian/Columbia University Medical Center in New York City. In 2019, he was elected to the board of directors for Doctors Without Borders USA.

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