Rising Research—Transmission Routes of SARS-CoV-2

By Leanne Low, Ph.D., Visiting Postdoctoral Research Fellow in the Laboratory of Malaria and Vector Research





A headshot of Julia Port, Ph.D.

Julia Port, Ph.D.

Credit
NIAID

Julia Port, Ph.D.

Credit:
NIAID

The “Rising Research” series aims to elevate the research conducted by NIAID intramural research fellows by featuring their work and stepping behind the bench to get to know the early-stage scientists who drive this work. The second article in the series summarizes the recent Nature Communications research paper by NIAID postdoc, Julia Port, Ph.D.

Julia Port, Ph.D., is a visiting postdoctoral fellow in the Laboratory of Virology at Rocky Mountain Laboratories. Her preliminary work was presented at the NIAID 14th Annual Fellows Virtual Workshop, earning her the award for best oral talk. This work has now culminated into her recent publication in Nature Communications, which contributes to our understanding of how different routes of exposure to SARS-CoV-2 results in different manifestations of the disease.  

“One of the things I really value about NIH is that it allows risk taking and really facilitates you to become independent, to think creatively, and to just move forward,” commented Julia, “I have greatly enjoyed the collaborative environment here at RML and the technical and methodological opportunities provided here.” — Julia Port, Ph.D.

With the rise of the COVID-19 pandemic, the scientific community has scrambled to discern as much as they can about its causative agent, SARS-CoV-2. For Julia Port, Ph.D., joining NIAID as a visiting postdoctoral fellow from Germany in February 2020 was not as she imagined, as she became one of many researchers to switch gears from their field of study to focus on mission-critical work. 

A tropical hemorrhagic fever virus virologist, Julia was set on doing a postdoc that would allow her to focus on comparing bat and human immune responses to severe, highly infectious viruses. “I met Vincent Munster at the European Virology Congress in 2019, and we found that we had really overlapping interests in that regard,” says Julia. A month after arriving at the Rocky Mountain Laboratories (RML) in Hamilton, Montana, Julia found herself diving into coronavirus-related work. “I came with high-containment lab experience, so at least I was able to quickly pivot and be of help in other projects, as well as run my own experiments,” stated Julia.  

The outcome of her efforts comes in the form of a recent Nature Communications paper, wherein Julia and her colleagues outline their findings on how exposure to the virus via different routes affects manifestation of disease and its severity. 

To shed light on this matter, Julia used the well-established Syrian hamster model to study three routes of exposure: intranasal, which entails direct administration of the virus into the nasal cavity and is typically used in scientific studies; fomite, from contaminated surfaces of objects/materials; and aerosol, through small liquid or solid particles suspended in air. “Aerosol exposure, because it deposits the virus probably more efficiently in the lower respiratory tract, leads to more early and severe disease,” said Julia. In contrast, fomite exposure led to mild disease. Julia speculated that “this is because the initial immune response starts in the upper respiratory tract, leading to a functionally controlled clearance of the virus before you really have lung pathology.” Release of the virus from host to the environment, or “viral shedding,” was also observed to differ between aerosol and fomite routes, with the former leading to early shedding and, consequently, increased disease severity.  

Julia also described the future for transmission studies that use a novel system the team developed. They found that while transmission by fomite was possible, it was far less efficient than aerosol transmission. “The strength of airborne transmission is really highlighted when there is a directional airflow. You can break that transmission…by redirecting the airflow,” said Julia. These preliminary transmission studies pave the way for aerosol transmission experiments that can characterize transmission over distances. “We designed a better system to characterize and modulate the droplets that travel between animals…this is a novel system that hasn’t been demonstrated before.” 

Next, Julia hopes to investigate novel variants, particularly the Delta variant, to determine how and why transmission is occurring more easily. 

While Julia acknowledges the difficulty of the past year of having to adjust to life during a pandemic, she expressed that the supportive and motivating nature of her work environment was pleasant. “One of the things I really value about NIH is that it allows risk taking and really facilitates you to become independent, to think creatively, and to just move forward,” commented Julia, “I have greatly enjoyed the collaborative environment here at RML and the technical and methodological opportunities provided here.”

She’d like to tell trainees who may be onboarding during the pandemic, “We’re not just doing science for the sake of science, we’re doing it for the sake of public health. I think that’s very important to keep in mind, especially if you work on COVID-19…but that doesn’t mean you can’t enjoy the science you’re doing. I found a way to combine something I’m interested in with what the lab is also interested in, and which is currently really relevant, and that is incredibly motivating and has made me more productive and energized.”  

See J Port et al. SARS-CoV-2 disease severity and transmission efficiency is increased for airborne compared to fomite exposure in Syrian hamsters. Nature Communications (2021), DOI: 10.1038/s41467-021-25156-8.
https://pubmed.ncbi.nlm.nih.gov/34404778/.

Press Release: NIH hamster study evaluates airborne and fomite transmission of SARS-CoV-2

Learn more about postdoctoral research training opportunities at NIAID.
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