Vaccines. Full coverage holds back Delta variant mutations, early data

Share

18 August 2021 The global coverage of the population with the Covid-19 vaccine is decisive to prevent the Delta variant, dominant in Italy as in most of the world, from accumulating mutations that make it more dangerous. This is indicated by the first data on this topic, relating to 16 countries including Italy and collected by Ting-Yu Yeh and Gregory Contreras, of the University of Maryland. 

The data is available online on the Medrxiv platform, which welcomes articles awaiting review by the scientific community. "We present the first evidence that vaccination coverage rate is inversely related to the mutation frequency of the Delta variant of the Sarscov2 virus in 16 countries," the researchers write, and

In light of these data, they note, global vaccination, i.e. of the world population, is crucial to prevent the transmission of the virus, and it is necessary to continue to adopt mitigation strategies and genomic surveillance. For the virologist Francesco Broccolo, from the University of Milan Bicocca, the research results are important, first of all because "in countries where more vaccinations are made, the chances of the virus reaching more dangerous mutations are reduced". 

It is also true, added the expert, that "the vaccination strategy alone is not enough: it is also necessary to continue to use prevention measures, such as wearing a mask and adopting distancing. They are all strong forms of virus reduction" . This is true, continues Broccolo, especially considering that the most recent data on the effectiveness of anti Covid-19 vaccines, published in the New England Journal of Medicine, indicate coverage of 88%. Looking only at the Italian data, continued the virologist, "the data relating to molecular swabs indicate that since the beginning of the summer the positivity index has increased by 5-6 times, passing from 1.2% of 16 June at the current fluctuations of between 6% and 9% ". 

"Precisely because the new cases increase it is emergency to re-discuss the mitigation measures that serve to block the circulation of the virus", broccoli noted again. These are measures to be considered "a complementary strategy to vaccination, even during the summer months". Equally important, for broccoli, are sequencing and genotyping, thanks to which "it becomes possible to find new mutations that allow us to understand if new variants are arriving that must be immediately blocked: if we do not sequence we cannot understand the spread of a new variant. , like

which could be hidden in the positive pads ".

For this reason, he added, "social distancing must be implemented with a new urgency in an attempt to prevent the transmission of the virus". Furthermore, "genomic surveillance should be undertaken urgently to monitor for new mutations".