In light of the greater contagiousness of the Delta variant, the percentage of the population that needs to be vaccinated to achieve herd immunity increases to about 88%. "Since the Delta variant is about 60% more contagious than the Alpha variant, it is necessary to reach a higher percentage of vaccinated people. In this way, even if the Delta were to be dominant in September, it will not be dangerous for public health", physicist Roberto Battiston, from the University of Trento, coordinator of the Observatory of epidemiological data in collaboration with Agenas, tells ANSA.
"Also in the light of data from England, the ongoing vaccination campaign may contain the impact of the Delta variant of the SarsCoV2 virus to the extent that the number of people fully vaccinated (second dose) will be high (today it is about 26% ). Most likely it will be a race against time, as was the one won, which allowed us to contain the Alpha variant, dominant from late February-early March ", he observes.
Although the appearance of outbreaks is inevitable, if in the meantime the intensity of the epidemic is further reduced, adds Battiston, "it will be possible to contain its effects to very low levels. vaccination". A high number of people vaccinated means strongly limiting infections and keeping the Rt contagion index well below 1, as it currently is. "We must aim as much as possible towards herd immunity because this will allow us to contain any outbreaks so that they cannot cause the fire to develop another wave.
88% herd immunity is "a challenging goal", Battiston notes, but it must be considered that "the more easily a variant is transmitted, the more it is necessary to protect the greater number of people with the vaccine, including people. younger, about 9 million in Italy between 0 and 19 years ".