New publications
The more mucus in the respiratory system, the more protected the influenza virus is
Last reviewed: 02.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Mucus and phlegm that accumulate in the respiratory tract create a kind of protection for the flu virus as it exits the respiratory system. This conclusion was made by scientists representing the universities of Pittsburgh and Virginia. They presented the results of their work on the pages of the University of Pittsburgh website.
In most European countries, as well as in the United States, the flu virus becomes more active with each coming of winter. This can be partly explained by the fact that people spend more time indoors, which makes it much easier for the virus to spread. In previous studies, scientists have determined that one of the likely factors for mass influenza virus infections is fluctuations in air humidity, which is associated with turning on the heating and sealing the windows. When virus particles are sprayed in a room with average or high humidity, the infection dulls its activity. Therefore, until recently, it was assumed that dry air allows the flu virus to survive and develop.
A new project by scientists has called this fact into question. It turned out that secretions that accumulate in the respiratory tract are released into the air during coughing or breathing of the sick person, simultaneously protecting the viruses. At the same time, the degree of humidity no longer has much importance.
Scientists simulated atmospheric conditions identical to real ones. The researchers wanted to see what would happen to the flu virus when it was released into the air with the breath of a sick person. The scientists assembled a special cylindrical rotating mechanism made of metal, which performed the function of constantly holding moisture particles in the air. Then they mixed various samples of mucus secreted from their respiratory tract, which contained the H1N1 flu virus. The virus particles were also passed through the cylindrical mechanism, which simulated the removal of infection through the respiratory organs of a sick person under normal conditions. A filtration system was pre-built into the mechanism, the function of which is to prevent the leakage of the pathogen. The study itself was carried out in a closed box, under conditions of complete biological impermeability.
The cylindrical mechanism changed the spray and humidity maintenance mode every 60 minutes during operation. There were seven such modes. Both a dry hot climate and a tropical humid climate were simulated. The following information was obtained as a result of the experiment: the influenza virus did not change its activity when the humidity mode changed. As the experts explained, the secretions accumulating in the respiratory organs create a certain protection for viruses, which survive at least until the moment of atmospheric parameters change. This time is quite enough for the infection to get to another person.
What can scientists advise in connection with the information received?
Researchers warn: with the onset of a period of widespread viral disease, it is necessary to use devices in rooms that clean and renew the air composition. Cleaning should be done by filtration or ultraviolet irradiation of a constantly circulating air flow. It is also necessary to disinfect objects that are most often in people's hands: this means chairs, tables, door handles, office supplies, computer mice and keyboards, etc.
Details of the study are described at http://www.upmc.com/media/NewsReleases/2018/Pages/kormuth-flu-humidity.aspx