Study of Microbial Exposure Continues To Expand in Wake of Covid

Given a global pandemic that has held the world in a vice grip for over two years, it’s not surprising that studies of viral transmission have become a lot more popular. 

Even now, as many countries emerge from the worst of the pandemic, it’s clear that preparing for the next variant of Covid-19 — or even the next virus — means improving our understanding of how microbes travel through the air. 


That’s especially important for workplaces, as the pandemic showed how swiftly viruses can spread without careful attention to social distancing and other safeguards for employees working in difficult conditions, like the U.S. meat-processing plants that fomented outbreaks of the virus early in the pandemic. 


In early 2022 alone, there have been many stories of new research projects aimed at technology that improves our ability to tackle airborne threats. 


  • In February 2022, MIT announced an air flow study conducted across 120 locations in all five boroughs of New York City. A team from MIT Lincoln Laboratory collected “safe test particles and gases released earlier in subway stations and on streets, tracking their journeys,” MIT News wrote. “The exercise measured how far the materials traveled and what their concentrations were when detected.” The 5,000 samples collected are still being analyzed. 


  • Another recent study from Japan looked at ways to reduce viral transmission in hospitals, especially among healthcare workers. Published on Research Square, the study is titled “Infection control for COVID-19 in hospital examination rooms,” and sought to understand what measures could reduce Covid-19 infections, which were frequently occurring despite the existing infection control procedures. It concluded that “a suction apparatus could reduce healthcare workers' aerosol exposure from COVID-19 patients by substantially removing both small and large aerosol particles.”

 

  • Yet another recent study, published in February 2022 and funded by the Norwegian Research Council, looked at “Dispersion of SARS-CoV-2 in air surrounding COVID-19-infected individuals with mild symptoms.” The study found that “SARS-CoV-2 RNA can be detected in air at a distance up to four meters from an infected individual presenting with mild symptoms, and that viral concentration in air within one-meter distance of infected individuals can be predicted by viral concentration in the upper airways, coughing, and mild fever…. This study should be useful for both detection and monitoring applications in air and for increasing our understanding of SARS-CoV-2 transmission dynamics.”


All of these examples dovetail with my own research as a postdoctoral researcher looking at bioaerosol transmission in different settings using cutting-edge molecular methods.


Working with many talented researchers, I supervised and co-authored a study about airborne viral transmission in a simulated Intensive Care Unit room. Published in the American Journal of Respiratory and Critical Care Medicine, it’s titled “Quantitative Assessment of Viral Dispersion Associated with Respiratory Support Devices in a Simulated Critical Care Environment.”


For the study, we used a simulated ICU room with a breathing-patient simulator exhaling nebulized bacteriophages from the lower respiratory tract. There were various respiratory “support modalities,” including:


  • Invasive ventilation (through an endotracheal tube with an inflated cuff connected to a mechanical ventilator)

  • Helmet ventilation with a positive end-expiratory pressure (PEEP) valve

  • Noninvasive bilevel positive-pressure ventilation

  • Nonrebreather face masks

  • High-flow nasal oxygen (HFNO)

  • Nasal prongs


Ultimately, the study’s results suggest that invasive ventilation and helmet ventilation with a PEEP valve had the lowest bacteriophage concentrations in the air. 


“These findings highlight the potential differential risk of dispersing virus among respiratory support devices and the importance of appropriate infection prevention and control practices and personal protective equipment for healthcare workers when caring for patients with transmissible respiratory viral infections such as SARS-CoV-2,” the study said.

While the world’s scientific community was able to develop vaccines for the Covid-19 virus in record time, the truth is that we still have much to learn about how viruses work — and how we can prevent their spread. 

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