How long can Coronavirus survive in the air and what is the true safety distance to be kept to avoid contagion? The virus, we know, is new and many studies are underway to understand how much it can really survive in the air.
Now research published in the scientific journal Practical Preventive Medicine (but later withdrawn for now without a clear reason) and cited by the South China Morning Post has concluded that the Coronavirus could remain in the air for at least 30 minutes and cover a distance of 4.5 meters indoors (such as a small bus, where the search was conducted), a distance well over a meter or two indicated by health authorities around the world.
The journey by bus
The researchers’ work drew inspiration from the case of positivity of a citizen, identified as “passenger A”, who made a trip on a crowded bus on 22 January, occupying a place in the penultimate row. The bus windows were all closed.
The individual, according to the analysis of the images recorded by the on-board camera, showed symptoms but did not wear a mask (the national crisis had not yet been declared). In the first leg of the journey, which lasted a total of 4 hours, passenger A infected 7 other people, including a couple sitting 6 rows apart. Passenger A (who did not interact with other passengers) at the end of the journey, boarded another minibus for an hour-long transfer. A total of 13 people are believed to have infected.
Roberto Burioni, professor of Microbiology and Virology at the Vita-Salute San Raffaele University of Milan, says that the data is too weak. “I don’t know the research in question but the data is very weak and the anecdotal study because it is based on the observation of these passengers through the camera closed circuit. Who tells me that the passengers weren’t already sick? And why didn’t those close to “passenger A” become infected? All we know is that the virus is transmitted through the droplets emitted by coughs and sneezes emitted by positive people and there is no real scientific evidence that the virus remains suspended in the air. A recent study on Jamahe studied the extent of coronavirus contamination when there was an infected patient with important symptoms: the air samples were negative despite the extent of contamination on some surfaces. And Jama is a serious magazine.”
“It is certainly an extreme case, which is not part of normalcy but in a closed context like a bus something like this could happen” comments the virologist Fabrizio Pregliasco, Health Director of the IRCCS Istituto Ortopedico Galeazzi.
“But we must remember that the further you move away from the infected subject, the less likely they are to be infected because the curve of the famous droplets drops. Furthermore, we can assume, apart from an observational study, that the “passenger A” was a super diffuser, with a high viral load and the people he infected were probably particularly susceptible, provided that the infection actually took place on the bus. In short, a series of particular circumstances, not so easily repeatable, but which must make us reflect on the importance of hand washing.”