Influenza, effective transmission only by coughing, stagnant air and close contact: results of a clinical study
A real-life study on infected and healthy people shows that proximity is not enough for contagion; coughing and room ventilation are decisive for the spread of the virus.
How is influenza transmitted most effectively (for the virus, not for us)? Is it enough to be close to each other at the table or to be in the same room to 'pass on' the invisible enemy of health? As we in Italy are about to reach the peak of cases, with the dramatic numerical push imposed by the K variant, comes research that offers valuable information in this regard.
Because it indicates how care must always be taken not to crowd into confined spaces, but reveals how proximity alone is not enough to 'pass on' viruses, and at the same time puts other modes of transmission that are more 'fruitful' for the virus (and therefore dangerous for us) under the magnifying glass. Rather than physical proximity to the sick person, in fact, coughing, the environmental stagnation of the air itself and really close contact (in practice 'vis a vis') would be the basis of optimal viral transmission. An experiment conducted by researchers from the University of Maryland at College Park and the Baltimore School of Medicine, published in PLOS Pathogens, tells us how influenza viruses spread and, above all, how best to protect oneself, in addition to vaccination, of course.
Coughing and air exchange
The research examined, in a real clinical study, the airborne transmission of influenza between naturally infected people, rather than intentionally infected in the laboratory, and uninfected people. It was coordinated by Donald Milton and Jianyu Lai, as reported in a University of Maryland memo. The experiment examined university students with influenza and healthy middle-aged adult volunteers, placed together in a hotel room. Basically, a real-life test.
Well, although it may seem strange, despite the close contacts none of the healthy participants contracted the infection. According to the experts, more than proximity there are certain variables to be taken into account. 'Our data suggest key factors that increase the probability of influenza transmission: coughing is one of the main ones,' is the comment of Lai, who analysed the data. What happened in the test? Although there was a high viral load in the nostrils, the students in the room only rarely coughed. So the amount of virus released into the environment was minimal. But that's not enough. Moving air would be the other key factor in the spread of viruses.
'The air in our study room was continuously stirred rapidly by a heater and a dehumidifier, thus diluting the small amounts of viruses present,' Lai said. Practical tip? Remember to open the windows often in the presence of flu symptoms. Finally, there is a further parameter that must be considered, age. According to experts, middle-aged adults tend to be less vulnerable to influenza than young adults, which probably contributed to the absence of infections.
