“To date, a total of 69 cases of the Omicron variant have been identified by targeted search for mutations and/or viral genome sequencing,” says the INSA report on the genetic diversity of SARS-CoV-2.

According to the institute, within the scope of real-time monitoring of the “failure” in the detection of the S gene, which allows the identification of the Omicron variant, carried out in collaboration with several laboratories, it was possible to gather data for the period from November 25 to 12 December.

"This analysis points to an increasing trend in the proportion of positive cases with S gene failure since December 6, reaching a relative frequency of 9.5% on December 12," the report said.

According to INSA, this trend, particularly that observed in the last three days, is "strongly indicative of the existence of community circulation of the Omicron variant in this period, in parallel with the scenario observed in other countries" that are using the same approach for surveillance of this variant, in the case of Denmark and the United Kingdom.

This new variant, which has been classified as “worrying” by the World Health Organization (WHO), has been detected in southern Africa, but since the South African health authorities raised the alert on 24 November, infections have been reported in more than 60 countries from all continents, including Portugal.