Catching the Flu May Be as Easy as Just Breathing
A new study about how people catch the flu shows that it is far easier to contract the virus than was previously believed, which may help explain why it spreads so rapidly.
According to new research conducted by a University of Maryland team, it appears that people can catch the flu just by breathing near an infected person.
Up until now, the common belief was that the flu is caught when an infected person coughs or sneezes near someone or by touching surfaces contaminated with the flu virus. All that is still true, of course, but the new research may change the way all of us need to think about being around people who are sick.
The big surprise in the study had nothing to do with how infectious the flu virus is. It was instead in discovering that the exhaled breath from flu sufferers is filled with very large quantities of the flu virus.
Dr. Donald Milton, M.D., PPH, Professor of Environmental Health at the University of Maryland School of Public Health and lead researcher for the study, said, “We found that flu cases contaminated the air around them with infectious virus just by breathing, without coughing or sneezing.” That discovery was bad enough, but the researchers also found that “people with flu generate infectious aerosols (tiny droplets that stay suspended in the air for a long time) even when they are not coughing and especially during the first days of illness.”
What that means is that the infectious field for a single sick person could stay in the air around them for a considerable amount of time, even if they are not coughing, sneezing or outwardly demonstrating any specific flu symptoms.
The research protocol included capturing exhaled breath from more than 142 confirmed cases of people with influenza. Tests were conducted in cases where the research subjects were simply breathing, where they were asked to speak and where they coughed or sneezed without prompting. Two hundred and eighteen nasopharyngeal swabs and another 218 30-minute samples of exhaled breath and spontaneous coughing and sneezing were evaluated one day, two days and then three days after the flu symptoms first appeared.
What the research team learned was that of the 23 samples they examined, which were collected around patients who were not coughing at all at the time, a full 48% (11 of the 23) had detectable RNA from the virus and eight of those contained the infectious virus itself. The team also noted that even when sneezing was present, there was not a lot higher presence of viral RNA copies than in the air contaminated by breathing alone. Among other things, that suggests that despite what had been previously believed, sneezing apparently has nothing to do with any active shedding of the virus into the air. In all cases, the size of the particles dispersed in the aerosol spread from breathing alone was fine enough to easily stay airborne and be an active contamination source.
As Sheryl Ehrman, Don Beall Dean of the Charles W. Davidson College of Engineering at San José State University, said about these discoveries, “The study findings suggest that keeping surfaces clean, washing our hands all the time and avoiding people who are coughing does not provide complete protection from getting the flu.” To avoid spreading the disease, she said that “staying home and out of public spaces could make a difference in the spread of the influenza virus.”the results of the study suggest that a flu outbreak may occur more easily and be much harder to stop than was previously believed. On the public health intervention side of the problem, more work is clearly needed to prevent the spread of the airborne particles in modern ventilation systems in offices, school classrooms and mass transportation systems such as subway cars. And on an individual basis, the old message that if you’re sick, you should stay home and not contaminate anyone else is also truer than ever.
These are wise words to heed, especially in a season with one of the worst flu outbreaks ever (particularly in the United States).
Now, someone just needs to figure out from where the flu really originates…