An ongoing study by the Società di medicina ambientale has found traces of coronavirus on fine particulate matter. However, it has not been proven that these particles are vectors capable of transmitting it.
True: traces of the Sars-Cov-2 virus have been found on fine particulate matter particles, the so-called fine particulate, in the air
False: it has not been demonstrated that the virus can spread, and consequently infect, by using particulate matter as a vector.
Following the recent study by Harvard University, which had found a strong statistical correlation between air pollution, and in particular the presence of pm2.5 fine particulate matter, and coronavirus mortality, another piece of research has attracted attention in recent days — entirely Italian, as it was produced by researchers from the universities of Bologna, Trieste and Naples, all members of the Società italiana di medicina ambientale (Sima) — whose findings have generated some confusion, partly due to the general press's limited familiarity with scientific topics. Or, as the Sima president, Alessandro Miani, himself puts it, "a certain superficiality".
First of all, it should be noted that the Sima study is not a completed piece of work, but only the first part of a paper that is still in progress. And it is Professor Miani himself who clearly explains to us what has been discovered so far and what has not been discovered, or at least not demonstrated: "We have discovered that the virus, the RNA genome — that is, the Sars-Cov-2 strand — can be present on atmospheric particulate matter. We found it in Bergamo in eight cases out of 22, where we had installed two samplers, but it can clearly be found anywhere else".
And here, in effect, all the proven new findings come to an end. After that, "the study will now continue with more samplers in Italy and abroad, to get a broader picture and potentially demonstrate the second step of our paper: is the virus alive on the particulate matter? What is its viral load and its capacity to infect?".
At the moment we do not know. Because the genome traced in Bergamo was not viable — it no longer had any infectious capacity: which is why claiming that particulate matter is a new vector of contagion, i.e. that it is capable of carrying the virus from one individual to another, is scientifically incorrect at this stage.
"The samplers were active for three weeks," explains Miani, "and only at the end did we take them for analysis, at the Trieste hospital authority and at the University of Trieste — and obviously, after three weeks, it was easy to imagine that the RNA found would be inactive. We will now carry out air sampling, analysing it every two hours at most, on the hypothesis that the virus may remain alive in the air for a few hours." To obtain results, assuming the research receives adequate funding, it will take more than a month.
If it cannot be said that fine particulate matter helps to spread the virus, what might this first, partial outcome of the study suggest? According to Professor Miani, finding traces of the virus in fine particulate matter — whether viable or already ineffective — "can become an important indicator of the presence of the coronavirus in a given area or environment", on the basis of which "appropriate measures to prevent a new epidemic can be identified at an early stage: health surveillance, the carrying out of rapid tests. This is something that the Arpa (the regional environmental protection agencies, ed.) can do right away". In short, for the time being all that can be done is to use the presence of the virus on the particulate matter as a warning sign of a possible outbreak, and take the necessary measures.
