The trend of coronavirus infections is downward, but the data could be linked to the increase in rapid antigen tests instead of molecular ones. For Francesco Broccolo, virologist at the Bicocca University of Milan, it is true that from 2 October to today there are fewer cases and yet the epidemic "is constant".

For example, examining the situation between 9 and 16 October, there was a 27 percent increase in the total number of tests - molecular and rapid antigenic - which went from 344,969 to 472,535, and at the same time the percentage of positivity, calculated on the basis of total tests, decreased from 0.7% to 0.6%: "A decrease - claims the virologist - due to an increase in antigenic swabs", which - speaking of the rapid ones - passed, in the two days considered, from 70% to 75% of the total. "The positivity rate of 0.6% and 0.7 - he explains - is a percentage that derives from a weighted average of the molecular and antigenic tests, an average that is affected by the large number of rapid antigenic tests".

And as Ferdinando Coghe, recently appointed medical director of the Aou of Cagliari, also points out, rapid antigenic drugs "have a lower sensitivity", while in particular in periods with a low prevalence of infection, molecular drugs should be used to identify and isolate cases.

In fact, rapid antigenic agents only recognize high viral loads, thus diagnosing many false negatives (and false positives).

(Unioneonline)

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