In a joint statement, the INSA and the General Directorate of Health (DGS) reveal that preliminary tests carried out at the INSA "strongly suggest that all 13 cases associated with Belenenses SAD players are related to the Omicron concern variant".

The health authorities also explain that the INSA, in analysing cases of infection of Belenenses SAD players, through its Department of Infectious Diseases, on Sunday analysed a batch of 13 positive samples associated with cases of infection in Belenenses players SAD, given that one of the positive cases had a recent trip to South Africa.

"In order to guarantee the breaking of transmission chains and following the precautionary principle in Public Health, while awaiting more information regarding the transmission, impact and vaccine effectiveness against the Omicron variant, the Health Authorities determined the prophylactic isolation of the contacts of the cases of infection associated with this outbreak, regardless of the vaccination status and the level of exposure", says the note.

These contacts - they add - "remain isolated and will undergo regular testing, as early as possible, on the 5th and 10th day".

The INSA also analysed samples from 218 passengers on a flight originating in Maputo, which landed on 27 November at Lisbon airport.

As for this flight, only two positives were detected: one is associated with the Delta variant and the other did not allow for correct identification.

The Ricardo Jorge Institute has already started genome sequencing for the final confirmation of these cases. However, the note adds, "the predictive value of the tests already carried out is very high".

This new genetic variant of the coronavirus, initially identified in South Africa and some southern African countries, has also been identified in recent days in some European countries.

"However, there is still no scientific data to support its greater transmissibility or its ability to reduce the effectiveness of current vaccines", refer the health authorities, who reinforced epidemiological surveillance, applying control measures, with the prophylactic isolation of contacts of cases of infection by the Omicron variant or with a history of travel to southern Africa in the previous 14 days, regardless of the vaccination status, according to the precautionary principle in Public Health.

The INSA will also continue to monitor the genetic variants of the new coronavirus on a continuous basis through the analysis of samples with national representation, as well as the analysis of suspected cases that are identified by health authorities or by collaborating laboratories", the note adds.

The national authorities also say that "Portugal is aware of this situation, maintaining its continuous program of monitoring of variants at national level" and continues to call for self-isolation and testing of people who have symptoms suggestive of COVID-19, who should contact the SNS24.