The Department of Infectious Diseases at the Ricardo Jorge National Health Institute (INSA) has already analysed 13,256 sequences of the genome of the new coronavirus, obtained from samples collected in more than 100 laboratories, hospitals and institutions, representing 297 municipalities in Portugal. “Among the new sequences analysed, the Delta variant (B.1.617.2) is the most prevalent variant in Portugal with a frequency of 98.3 percent in week 29 (19th to 25th of July) being above 95 percent in all regions”, states the “Status report on the genetic diversity of the new SARS-CoV-2 coronavirus in Portugal” published today on the INSA website.
According to the data, the relative frequency of the Delta variant in this period was 100 percent in the North, Algarve and Autonomous Region of Madeira, 97.6 percent in the Center and Alentejo regions, 97.2 percent in Lisbon and Vale do Tejo and 95 percent in the Autonomous Region of the Azores. The INSA researchers say that, of the total Delta variant sequences analysed to date, 62 have the additional K417N mutation in the Spike protein (AY.1 sublineage). “This sublineage has maintained a relative frequency below 1 percent since week 24 (14th to 20th June) , with six cases having been detected during the period of weeks 28 (12th to 18th and 29th July) and 29th (July 19th to 25th). )”, they refer.
The SARS-CoV-2 genetic diversity report also indicates that the relative frequency of Beta (B.1.351) and Gamma (P.1) variants, initially associated with South Africa and Brazil (Manaus), respectively, maintains is down and without a rising trend. Both had a frequency of 0.4 percent at week 29, according to data collected to date, they emphasize, adding that no new cases of the Lambda variant (C.37) were detected, which has marked circulation in the regions of Peru and Chile.
Among other variants of interest in circulation in Portugal, the INSA highlights variants B.1.621, initially detected in Colombia, and Eta (B.1.525), initially detected in Nigeria, which have mutations in the Spike protein, which are shared with some of the worrying variants. These variants have a low frequency in Portugal, having been detected below 0.8 percent (B.1.621) or 0.3 percent (Eta B.1.525) since week 25 (21 to 27 June), the document states.
As part of the continuous monitoring of the genetic diversity of SARS-CoV-2 that INSA is developing, an average of 601 sequences per week has been analyzed since the beginning of June 2021. This sampling involved laboratories distributed throughout the 18 districts of the continent and the autonomous regions of the Azores and Madeira, covering an average of 118 municipalities per week.
As of June, the INSA adopted a new strategy for continuous monitoring of the genetic diversity of the new coronavirus in Portugal, which is based on weekly nationwide sampling. “This approach will allow for a better genetic characterization of SARS-CoV-2, since the data will be analyzed continuously, and there will no longer be time intervals between analyses”, stresses the institute.