"Since December 6, there has been a high growth in the proportion of probable cases of the Omicron variant, having reached an estimated proportion of 89.6% on January 3, 2022", says the INSA report on genetic diversity of SARS-CoV-2, which causes Covid-19 disease.

According to the institute that monitors the evolution of the coronavirus in Portugal, the “sudden increase” in community circulation of this variant resembles the “scenario observed in other countries”, such as Denmark and the United Kingdom.

The first 13 cases of Omicron in Portugal were detected at the end of November, associated with an outbreak in Belenenses SAD and the same transmission chain, but on December 6, the INSA said that 37 cases had already been registered.

A week later, on December 14, and with only 69 cases detected, the INSA report admitted the community circulation of Omicron, which was confirmed on the 20th of the same month, when the variant was already responsible for an estimated proportion of 46.9% of infections.

With the Delta variant progressively losing ground after having been dominant for several months, Omicron was responsible for 82.9% of infections recorded at the end of the year.