The INSA bulletin on epidemiological surveillance of respiratory viruses, relating to the period between 30 December and 5 January, indicates that, in recent weeks, “a growing trend in influenza cases has been observed” in the country, which presents an “activity epidemic flu with a growing trend”.

In the first week of this year, there was a “higher than expected mortality rate in the over-85 age group and in females,” the institute said.

“In the 2024/2025 season, the laboratories of the Portuguese Network of Laboratories for Diagnosis of Influenza and Other Respiratory Viruses (hospitals) reported 41,778 cases of respiratory infection and 4,341 cases of influenza were identified”, says the document.

In the week between December 30 and January 5, 1,048 positive cases of the influenza virus were identified in this network.

INSA also reports that, this week, eight cases of flu were reported by the 16 intensive care units that sent information and that, of this total, four had chronic disease and seven had a recommendation for vaccination against seasonal flu, but only one was vaccinated.

This week, the proportion of flu cases in intensive care was 5.5%, increasing compared to the previous week (2.9%), the bulletin also reports.

As a preventive measure, authorities have insisted on seasonal vaccination, which began on September 20 and has already allowed more than 2.3 million people to be vaccinated against the flu and around 1.5 million with the booster dose against Covid-19.