Coronavirus: 5,080 new cases and 198 deaths in the last 24 hours
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May 10, 2021The number of vaccinated people is growing, the epidemic data is decreasing. And with the change in the scenario, the risk assessment model is starting to be modified, as announced by the president of the Istituto Superiore di Sanità (Iss) Silvio Brusaferro on 7 May: "We must provide sensitive tools that give us early 'alert in the event of outbreaks or situations of increased circulation of the virus in order to be able to contain it quickly. This allows us to intervene in a more surgical way and to deal with the possible circulation of new variants ".
The working group for the identification of new parameters, promoted by the Ministry of Health, which also includes the Regions, the ISS and the Scientific Committee, is currently finalizing its evaluations.
For his part, Undersecretary for Health Andrea Costa stated that it would be "reasonable and decisive to evaluate the use of new parameters with respect to RT to determine color bands and new openings".
Meanwhile, the data of the latest monitoring speak for themselves: a slight increase in the transmissibility index Rt, which is located at 0.89 but always below the unit's alert threshold, is not matched by a restart of the epidemic and the the case curve is decreasing for the first time on the whole national territory.
So far, the criterion adopted by the ISS to calculate Rt (the value indicates the number of people who can be infected by an infected individual) has been based on the count of positive symptomatic cases by comparing them with those of the previous week. To ensure greater accuracy, the comparison was made between the data of the penultimate week with those of the third last week. Hence the problem of delay.
In reality, there are several ways to calculate the contagion index Rt (from the number of symptomatic positive cases, to the relationship between cases and tampons, up to entry into intensive care) and now the challenge is to choose the most effective in following the course of epidemic in the coming months.
Alternative models have been developed to solve the problem. For example, there are those who measure the relationship between positive cases and swabs, from which the positivity index is deduced, and then this value is compared with that of the previous week.
Another technique calculates the ratio of one week's ICU admissions to those of the previous week. A method that is not affected by the oscillations due to tampons, and is used by physicist Roberto Battiston, of the University of Trento. "This method could be more convenient for the Regions as vaccinations of the elderly reduce the entry into intensive care: consequently the RT could remain low even in the face of an increase in infections", observed physicist Giorgio Sestili, founder of the Facebook page 'Coronavirus-Scientific data and analysis' and the science communication network 'giorgiosestili.it'. "No method is infallible - he concluded - and now we need to understand which is the most effective for monitoringepidemic in the coming months, rather than the most comfortable to stay open. "