A new variant of the coronavirus slightly modified compared to the Delta, baptized by the international media, is spreading around the world Delta + (about Plus). The strain is actually called B.1.617.2.1 O AY.1, and was identified in India by the Institute of Genomics of the National Research Council and is present in three states. According to reports from CNN in the United Kingdom, a country that has always carried out many genomic investigations by sequencing at least 10% of positive swabs, the first cases would have been reported as early as April 28, so it probably circulated since spring. To date, around 200 cases have been identified in 11 different countries. Public health experts are studying the Delta Plus to be more transmissible than Delta and Alpha, although a response is still premature given the limited number of samples sequenced so far.
What are the differences between Delta and Delta +?
All variants have different mutations. Delta Plus compared to Delta has one more mutation called K417N. This is a mutation in the Spike protein, the part of the virus that attaches to the cells it infects. The K417N mutation is not entirely new and has arisen independently in different viral lineages. common to the Beta variant (which spread to South Africa) and also to a strain found in Qatar in March 2020.
How concerned should we be with this variant?
According to the Indian government’s COVID-19 Genome Sequencing Agency, the Delta Plus variant has several troubling traits such as increased transmissibility, stronger binding to lung cell receptors and a potential reduction in antibody response. It is not yet clear what effect the mutation may have on vaccine efficacy, but Julian Tang, a professor of respiratory sciences at the University of Leicester, warned that it could potentially give the variant the ability to escape vaccines. However, scientists urge everyone to be cautious and calm, while maintaining attention because there are still few reported cases.
There are no particular reasons for concern at this stage: it is a Delta with the K417N mutation in the spike protein, says Francois Balloux, professor of computational systems biology and director, UCL Genetics Institute. The variant was first seen in India on April 5, 2021 – adds the scientist – but its prevalence remained extremely low, with the exception of Nepal where a prevalence of around 4% was estimated on a very small sample. Delta + now represents 0.00002% of all delta variants sequenced to date. There is no evidence that the strain is currently expanding to any country.
We still don’t know if AY.1 has any advantage over Delta, but it seems unlikely since the only difference is the K417N mutation, Professor said. David Robertson, head of viral genomics at the Center for Virus Research in Glasgow. There is no evidence that AY.1 is more transmissible or that it escapes vaccine-induced immunity. The mutation has also been seen in some subspecies of Alpha, without a significant increase in case expansion. Probably no longer infectious, but it may affect post-vaccine antibody response.
What do we know about transmissibility, lethality, vaccination evasion?
Given the small number of reported strains – explains Francois Balloux – nothing is known about the transmissibility, immune evasion or lethality of the Delta + strain. However, since it has remained at a very low frequency in the places where it was identified, it is likely that it is no longer transmissible than its ancestor Delta
What is the K417N mutation?
The mutation K417N arose independently in different lineages (at least twice in the Delta). was observed on March 27, 2020 in a strain found in Qatar. K417N generally present in the beta variant (1.351), the former South African. This mutation could contribute to immune escape, although its impact on transmissibility is unclear. None of the lineages containing K417N have been successful in spreading so far, with the exception of the Beta.
Where is Delta Plus distributed?
So far, Delta Plus has been reported in 11 countries, but the number of cases per country reflects the number of samples that have been sequenced and more data is needed to determine the actual spread rate. As of June 16, 83 cases had been confirmed in the United States, 14 in the United Kingdom (all people who had traveled to Nepal and Turkey). India has counted 40 cases, spread across three states: Maharashtra, Kerala and Madhya Pradesh. The rest of the cases spread across Canada, Japan, Nepal, Poland, Portugal, Russia, Switzerland and Turkey.
June 25, 2021 (change June 26, 2021 | 11:27)
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