Vaccinated Flu Patients Might Shed Infectious Fine Particle Viral RNA More Than Others, New Data Suggests

Dawn Papple

Multiple media reports warned us that simply breathing the air around someone sick with the flu might cause us to become infected thanks to fine particle viral RNA. Researchers at the University of Maryland School of Public Health reported in the Proceedings of the National Academies of Sciences that fine aerosol particles collected from the air around patients infected with influenza contained detectable flu virus. Merely exhaling releases the virus into the air if someone is infected. This fascinating new research triggered social media alarm about the flu virus, but there might be even more to the story.

"There's not much evidence that any of that works very well," Professor Milton told a Time Magazine reporter. "Surgical masks block mostly the large droplet spray, but the surgical masks don't block the fine particle aerosols very well. The route of infection matters."

Earlier research conducted by the university showed that surgical masks only reduced fine particle aerosols by 2.8 fold. Yet, in the large particles, the viral copy numbers were reduced by 25 fold by wearing a surgical mask. The large particle viral RNA is not the so-called airborne kind. They are not the particles in the media spotlight about this newly published research.

Smithsonian Magazine reported that they are currently trying to figure out if these infectious fine particle aerosols actually transmit the flu.

Indeed, these early results showed that the people that had been vaccinated against the flu two years in a row (but still became infected with influenza A) shed more virus in the fine particle aerosol than other people with influenza A or B. They didn't shed more into the swab of the nose, but the airborne virus data gathered from these repeat-vaccinated people is surprising. The number of participants was clearly very small. The information needs to be confirmed and studied in depth before making any conclusions.

Could further research lead to new recommendations on how to prevent transmission in hospitals, classrooms, subway cars, and other enclosed spaces? According to Science Daily, improvements could at least be made to ventilation systems inside offices, schools, and public transportation at the least to reduce the number of flu cases.

The new research from the University of Maryland certainly makes one thing clear: if you're starting to show symptoms of the flu, stay home! You're most infectious at the start of the illness, and no one wants your fine particle aerosols!