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Influenza is spread through normal breathing
Last reviewed: 02.07.2025
Probably, everyone, young and old, knows this: the spread of flu viruses is carried out by airborne droplets. The smallest viruses "hide" in no less small particles released at the moment of coughing and sneezing from the mouth and respiratory organs of the sick person. Almost all people who hear sneezing or coughing next to them try to turn away or move as far away as possible - such behavior can already be classified as acquired instincts. But, as it turned out, for the sick person it does not matter much how to spread viruses. At the same time, he may not cough or sneeze: the flu can spread around the patient even during normal breathing.
Scientists representing the University of Maryland monitored the condition and behavior of almost one and a half hundred people sick with influenza infection. In some patients, the first clinical signs of the disease appeared yesterday or today, and in others - a couple of days ago.
People with the flu were observed: some coughed or sneezed, and some simply breathed. The air that was released from the participants' respiratory organs for 30 minutes was sent for examination regarding the presence of viruses in it. The presence of viruses was determined both by RNA and by whole virus particles.
In approximately every second case, when taking air samples from patients without signs of coughing or sneezing, relatively high RNA viruses were present in the suspended particles. And the overwhelming majority of such samples contained whole virus particles.
Thus, as has already been noted, a person with the flu infection "shares" the virus even when performing normal breathing movements, and coughing and sneezing are not at all necessary for spreading. In addition, the researchers found that at the time of sneezing, the concentration of the virus in the air is not as high as previously thought. Therefore, sneezing may even be less dangerous in terms of spreading the virus than the normal breathing of a sick person. According to experts, it is breathing that releases the most viruses into the surrounding atmosphere.
The information obtained during the study may become an impetus for the creation of new, more effective preventive measures aimed at reducing the spread of viral infections (possibly not only influenza, but also other acute respiratory viral infections that are transmitted by airborne droplets). It is quite possible that in the future, epidemiologists will more objectively determine the potential danger and prevalence of seasonal viral attacks.
Ordinary people should also draw certain conclusions. If a person does not cough or sneeze at the initial stage of influenza, this does not mean that he has the right to go out into society. Even through normal breathing, an infected person can, without knowing it, transmit the disease to a huge number of people.
Details are presented in the pages of PNAS.
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