Covid: the Delta variant continues to spread, tests are coming to recognize it
In Italy, new tests will soon be available that can also recognize the Delta variant of the new coronavirus, which is spreading faster and faster in several European countries. The variant, first detected in India, has already become dominant in Portugal and the UK in a few weeks, prompting the British government to postpone the end of restrictions in England by one month.
The new tests will make an important contribution to monitoring the circulation of the variant, 60 percent more effective in transmitting than the Alpha variant (identified for the first time in England) and with a 2.2 times higher risk of leading to hospitalization. The virologist Francesco Broccolo, from the University of Milan Bicocca and director of the Cerba laboratory in Milan, told Ansa, recalling that “only a little more than a quarter of the population was vaccinated with the double dose” and that “vaccines do not they are the only solution “.
For this reason it is necessary “to modify the criteria for screening as soon as possible and to update the tests for the search for variants that cause concern” since the current procedures consist “of swabbing with tests that are not updated on the current Italian epidemiological framework, which foresees the presence of the Alpha variant in 95% of positive swabs “. “We don’t have circulation monitoring of this variant, unlike in Britain, where a national sequencing program is in place,” he said.
Compared to those currently used for diagnosis, the new tests do not look for mutations in the spike protein, used by the virus to invade cells, but for a mutation called N501Y, present in all the main variants known so far except in the Delta. The absence of the mutation “would immediately trigger the new diagnostic algorithm, which could include the immediate search for the Delta variant,” Broccolo said.
This can be found thanks to “a variant capture test capable of detecting specific mutations of the Delta variant, such as L452R”, but also mutations such as K417N and E484K present in the Beta and Gamma variants, identified respectively in South Africa and Brazil, ” which are known to escape, at least partially, vaccines after the first dose and in some cases after the second “.
According to an estimate by the Financial Times, based on data from the Gisaid virus tracking database, 26 percent of new cases sequenced in Italy are attributable to the variant, compared with 15 percent in Germany and 6.9 percent in France. The UK and Portugal, on the other hand, are at 98 and 96 percent respectively.
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