Coronavirus, the turning point with the “erre with zero” value lower than 1: what it means

When will we be able to say that we won it against the coronavirus? From a mathematical point of view, only when the R0 value (the zero-zero, the contagiousness index) will be less than 1. It means that it will be necessary to arrive at the moment when for each infected individual there will be less than one new infected person.

This is explained by the professor Pierluigi Lopalco, epidemiologist and professor of hygiene at the University of Pisa, coordinator of epidemiological emergencies of the Puglia Region. According to the expert, to say when Italy will be truly “safe” from the coronavirus, it will be necessary to wait for “the infection rate to be less than one, that is, when a positive person has the potential to infect less than another person. However, it is difficult to say now when this will happen. ”

Coronavirus, “safe only when the infection rate is less than 1”

For the scientist, in fact, “they are still there too many unknowns and a few weeks of close surveillance of the cases will be necessary. “The interruption of the epidemic, explains Pierluigi Lopalco,” occurs when the transmission index defined as ‘R with zero’ is below 1. This can be seen from different parameters starting from the number of cases and the estimate of the share of people who can still contract the disease compared to those who developed the antibodies “. However, it is now” very difficult – warns Lopalco – to be able to say when we will reach the R value with zero less than 1. Much depends on the trend of the epidemic in Lombardy and we hope that there will be no further increase in cases in Milan. At the moment, that is, there are too many unknowns “.

Before the introduction of the restrictive measures, in Lombardy it had also reached a value of R0 = 4, that is, a positive person infected another four.

Coronavirus, Lopalco: “Extreme caution is needed”

Compared to the general trend of the epidemic curve, the epidemiologist notes that “there is a slowdown that gives us hope, but extreme caution is needed before we can say that we have turned. The spread of a day is what actually goes back to contagions of at least a week before, so before pronouncing you must be sure that the trend stabilizes “. What is certain, finally notes the expert, is that “the measures adopted are bearing fruit, but at the moment it cannot be said when there will be a drop in daily cases because new outbreaks could open, as well as the so-called peak it’s an abstract and relatively relative concept. “

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