While infections are growing exponentially in many countries in Europe, with Bulgaria reaching the record of 5,863 new cases registered in the last 24 hours and 243 deaths, and Belgium that with 5,300 new positives per day records a 75% increase in cases compared to last week, all the curves of the Covid-19 epidemic also date back to Italy.

Values such as the Rt contagion index, which exceeded 1, and the positivity index are traced back: therefore, maximum attention, even if by experts there is a "cautious optimism" due to the high percentage of vaccinated people and the introduction of the Green pass.

NEW VARIANT - The unknown factor of the sub-variant AY.4.2, the so-called “Delta plus”, which currently can only be intercepted thanks to sequencing, but not by tests, keeps the attention awake. "At the moment - observes virologist Francesco Broccolo, of the University of Milan Bicocca - genotyping tests do not distinguish it because it has mutations that are not searched for with usual tests. The only way to detect it would be carpet sequencing".

According to the data released yesterday by the Ministry of Health, the positivity rate increased in 24 hours from 0.9% to 1.1%. By calculating the ratio between molecular tests alone and rapid antigenic agents, the positivity rate is 4.8%, thus confirming the progressive increase in this epidemic index which has now emerged for a few days.

"In the last week, the increase in positivity detected by molecular tests has increased from 2.89% on October 17 to 4.25% on October 24," notes Broccolo.

THE INCIDENCE - According to the analysis of the mathematician Giovanni Sebastiani, of the Institute for the Applications of Calculation "M. Picone", of the National Research Council (Cnr), there are 18 regions in which the incidence is increasing in the last week compared to the previous week. In general, says Sebastiani, "all the curves of the epidemic at the national level are growing, from the percentage of positives to molecular tests to the incidence of total positives to molecular tests and rapid antigenic tests, up to daily entries in intensive care. There is also a weak daily increase in the average death curve ".

The contagion index Rt also goes up and exceeds 1: the Covindex is equal to 1.25, the parameter that can be superimposed on the Rt index and updated on the basis of the ratio between new positive cases and swabs, calculated by the researchers who report to the CovidTrends site ; CovidStat managed by experts from the National Institute of Nuclear Physics (Infn) is equal to 1.04.

"Now it is a matter of understanding whether the Covid-19 epidemic is recovering or not", observes physicist Giorgio Sestili, founder of the Facebook page "Coronavirus-Scientific data and analysis". According to the expert, "the situation must be monitored in careful way as it is likely that in the coming weeks we could see an increase in cases, considering the arrival of winter and the spread of the flu ".

(Unioneonline / vl)

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