According to the most recent situation report on the genetic diversity of SARS-CoV-2 in Portugal, released by the INSA, the Delta variant, initially associated with India, has seen “a dramatic rise” in relative frequency at the national level, but its distribution “is still very heterogeneous between regions”.
According to INSA, the distribution of the delta variant varies between 3.2 percent (Azores) and 94.5 percent (Alentejo) but taking into account the trend observed between May and June, “it is expected that this variant will become dominant in the entire national territory during the coming weeks”.
Of the total number of Delta variant sequences analysed to date, 46 have the additional K417N mutation in the Spike protein, the institute says.
However, he stresses, about 50 percent of these cases are restricted to just two local transmission chains, which suggests that their community circulation is still limited, with the relative frequency of this profile (Delta+K417N) in the national sample June 2.3 percent.
According to the report, among the new sequences analysed, the Alpha variant (B.1.1.7), initially associated with the United Kingdom, was detected by sequencing with a relative frequency of 40.2 percent in the June national sample, showing a strong reduction in attendance nationwide (88.4 percent in May).
However, explains the INSA, “this variant is still the most prevalent in the North region (62.7 percent) and in the autonomous regions of the Azores (96.8 percent) and Madeira (69.8 percent)”.
The Ricardo Jorge Institute report also reports that the relative frequency of the Beta (B.1.351) and Gamma (P.1) variants remains low, with no upward trend in the latest samplings.
“In particular, it is noteworthy that the Beta variant was detected at a frequency of 0.1 percent and in only two regions (Lisbon and Vale do Tejo and Região Autónoma da Madeira)”, he says.
According to the document, to date 9,846 sequences of the genome of the new coronavirus have been analysed, obtained from samples collected in more than 100 laboratories, hospitals and institutions, representing 284 municipalities in Portugal.
As part of the genomic surveillance that INSA is coordinating, 1,087 sequences were obtained from the national sampling for June 2021, which took place from 2 to 15 June. This sampling involved laboratories distributed throughout the 18 districts of mainland Portugal and the Autonomous Regions of the Azores and Madeira, covering a total of 131 municipalities.