Q&A: Hospital Airflow Plays a Crucial Role in Infection Prevention

Infection Control Today®:In terms of infection, and how infection travels, have there been any new studies or breakthrough findings about how buildings should be laid out.

Stephanie Taylor, MD:That’s a very good question. And one of the things that I have found in my work is that initially, the building metrics that we follow even healthcare facilities as well as other commercial buildings have had more to do with how much energy is being consumed, because that’s a clear cost for a hospital or any other building. One of the shifts that we’re seeing and one of the shifts that COVID-19 has actually accelerated is the focus on how to manage a building to actually protect the occupant health. As you mentioned, I’ve been working in this area now for, I don’t know, 15 years, because in my medical practice, I became concerned that the building had a role in patient infections. When I began to do research actually using patient outcomes as a metric for the building, lo and behold, certain indoor air management strategies stood out as being either protective or putting people at risk. And so, there have been a couple of shifts. And thankfully, we also have some new ways of actually understanding the relationship between indoor air management and human health in hospitals, schools, medical office buildings, even in our homes. So the short answer to your question is yes, we definitely have some new information about how important building management is for infection control.

ICT®:Airflow will become even more important thanks to COVID-19. Is that a fair assumption?

Taylor:It’s a very fair assumption. And the indoor environment has always been an important component of human health. And if you think about how the average human being spends 90% of their time indoors. So COVID-19 has really focused our attention on how a building can either protect us or not from disease. It’s always been important, but people are now aware of the importance of managing the building to prevent health problems.

ICT®:How cognizant are infection preventionists about the importance of airflow?

Taylor:That’s a great question. And it’s also a complicated answer, because I think human nature is that we want to address transmission routes that we have some control over. If you think about airborne transmission, that’s probably the hardest route to control. So going back in time—not to be a historian here—but going back to the Bubonic plague, the transmission route that was assigned was fleas from rats, because you can see a rat, you can stop a rat. However, in 2018, those corpses were exhumed and we found that actually the airborne transmission route was huge. So, back to your question. Infection preventionists tend to focus on behavioral strategies for reducing transmission of pathogens; bacteria, viruses, the microbes that cause disease. However, there is acknowledgement that the air is important for certain diseases: measles, tuberculosis, influenza. However, in general, airflow has been managed by the engineers, by the architects, by the facility managers and not so much by the clinicians. There is a lot you can do in indoor air management to decrease transmission of infections. And my research has made me focus on how we can actually intervene in controlling aerosolization of, for example, right now COVID-19. There is a lot we can do, and I’ll tell you what that is, if you want me to.

ICT®:Sure, please.

Taylor:In my initial studies, when I didn’t really have any idea of which component of the indoor environment might contribute to infections or prevent infections, I was really open to whatever the data was going to show me. And what has come to light again and again and again. And it’s sort of anti-intuitive, is that when the air is overly dry, we actually have increased transmission of infections. And so this was a surprise to me. But since that time, through further research of mine plus many other people, we are now finding that to decrease the transmission of infections indoors, there’s an optimal range of relative humidity that happens to be 40% to 60%. Humidity indoors that is actually optimal for human beings. Our immune system is the most robust, and other organ systems as well. Our brains work better, for example. And in this range 40% to 60%, we’re also finding that pathogenic or disease-causing bacteria and viruses are both less infectious and they’re fewer of them in the air in the airborne environment where we can breathe them in. To my great surprise, 15 years ago, that this zone of relative humidity as being so important. It’s become clear to me and again to many other people.

ICT®:You first got into this when you were a physician. You went back to school and became a certified infection preventionist. You also went back to school for architecture. Do you think the two fields can talk to each other now to figure out a better way to improve airflow not only in buildings under construction even in buildings that have been around for a long time?

Taylor:I think that the that the medical profession and the building profession, whether it’s architecture, engineering, facility management; we do need to be talking to each other. Do I think that’s easy? No, I think it’s actually quite difficult for several reasons. I think the more competent you are in your field, the less willing you are to embrace a whole other body of knowledge that you don’t know anything about. I personally found it very difficult to go back to architecture school in my 40s and learn a whole new way of thinking.

ICT®:That’s pretty impressive., by the way.

Taylor:Well, thanks. It was hard and it gave me more respect for the difficulties in different professional groups communicating with each other. And yet, if we don’t, if we ignore the impact of the environment and indoor air, specifically, on our health, we’re missing the utilization of one of the most effective toolboxes for controlling infections. It’s just absolutely…. It’s exciting that we do have the ability to manage the indoor environment. And there are also significant obstacles. They mostly have to do with our willingness to accept new concepts.

ICT®:You mentioned environmental services. How do they fit into this and or do they?

Taylor:Actually, the facility manager and housekeeping are critical to optimal patient outcomes. Unfortunately, sometimes, I think, how some of the custodial positions are not educated about how important their work is in patient outcomes. As a physician, we weren’t taught anything about the building. And I don’t think that building professionals are taught enough about human health. But in a hospital for example, managing filtration, managing indoor humidification, managing proper pressurization of patient rooms is absolutely key to whether or not that person is going to leave the hospital when they hope to, and leave in good shape. So environmental services are as important in my opinion as a lot of clinical medicine that we practice in inpatient settings.

ICT®:So infection preventionists: What concrete steps can they do to monitor what’s going on with airflow?

Taylor:Well, that’s a good question. I mean, the first thing an infection preventionist can do is to realize that the environment is critical. And in my research, we’ve learned that low humidity in the patient room is harmful. So, as an infection preventionist, you can be aware of this, you can in meetings try to inform and educate the building component of clinical care about the importance in this case of humidification. You know, beyond that, it’s hard to know what the role of an infection preventionist is in managing the hospital building. But I think being aware, being educated, and being vocal about air about humidification is really a step forward. So if you have mold, or if you have a humidification system or ductwork that’s been inactive or closed down, you don’t want to turn it on and just dehumidify your air because the result will be that you will be disseminating into the breathing zone of people, all of the segments of, for example, mold that can cause respiratory disease.

This interview has been edited for clarity and length.