UMD to Lead $15M Project Investigating the Role of Aerosols in Flu Transmission

When it comes to contracting the flu or other respiratory viral illnesses such as COVID-19, medical experts have long believed the primary culprits were contact with contaminated surfaces or being sprayed by droplets from someone coughing and sneezing nearby. However, several recent studies have put the spotlight on aerosols—tiny particles that remain suspended in the air after an infected person breathes or speaks—as the dominant transmission route.

Research over the last 20 years by School of Public Health Professor Donald Milton, M.D., has been central to this discussion, and now, Milton and collaborators could put to bed the debate over how viruses spread with help from a $15 million research award from the National Institutes of Health to develop new technologies for collecting viruses from the air and conduct a five-year randomized, controlled trial.

“The medical community doesn’t yet fully understand aerosols and has been waiting for more evidence from a trial like this one,” said Milton, who will lead the project. “My hope is that we can address this persistent controversy that has held up our ability to respond to respiratory pandemics.”

As part of the project, researchers at the University of Maryland School of Medicine, led by Dr. Wilbur Chen, will recruit groups of healthy people whose antibody levels make them susceptible to influenza and are unvaccinated) to volunteer to live in a quarantine facility watching movies and playing cards, pool and video games together for about two weeks. Researchers will also recruit people diagnosed with influenza to come stay in the quarantine facility and interact with the healthy people.

To understand how influenza virus is transmitted, investigators will use two interventions: To block transmission by close-range droplet spray, some of the healthy participants will be asked to wear face shields and wash their hands every 15 minutes, while others will not be given those precautions. To test the role of airborne transmission, a team led by UMD mechanical engineering Professor Jelena Srebric will design special ventilation systems. Some groups will be in the quarantine facility in rooms with low ventilation and exposure to viral aerosols is high. Other groups will be in rooms where advanced ventilation systems, including germicidal UV-C lights, will eliminate the vast majority of exposure to airborne viruses. The study will compare how the flu spreads within the different scenarios.

“That way we can separate out what transmissions can be attributed to aerosols, or to spray and touch,” Milton said.

Participants with flu will also be asked to speak or sing into the Gesundheit II machine designed by Milton to capture and measure aerosols in exhaled breath. The researchers will also collect breath and room air samples using newer technologies being developed by a part of the study team led by Don DeVoe, UMD professor of mechanical engineering.

This new research will build upon a previous study Milton helped lead in 2013 and published last year that evaluated flu transmission from healthy people who were artificially infected via nose drops. Results from that study were some of the first to build evidence that aerosols play a big role in spreading the virus between humans.

Collaborators on this new NIH-funded project will also include scientists from the Mt. Sinai Icahn School of Medicine, University of Michigan School of Public Health, University of Wisconsin School of Veterinary Medicine, Hong Kong University School of Public Health and Aerosol Dynamics Inc. in Berkeley, Calif.