At a news conference in Lisbon, the director-general of health, Graça Freitas, described the season as one of low to moderate intensity, without much impact on mortality and morbidity.

According to Freitas, this year’s peak has already passed, with activity now on a downward path.

She stressed that more than two million Portuguese have been vaccinated against the flu – more than ever before.

“In the National Health Service alone [with the vaccine free] we have vaccinated about 10% more than in previous years,” she said. “And vaccines in pharmacies have also increased."

Despite the moderate intensity and the current downward trend in mainland Portugal, however, there are regional differences in flu activity.

For example, the Alentejo region did not have epidemic activity this year, while the Algarve is now entering the epidemic phase. In the North and Centre of Portugal the trend is downward, while in the Lisbon and Tagus Valley region, the flu is "on a plateau": stable and still without activity decreasing.

"To date, with all surveillance systems, everything indicates that we have had a low to moderate flu activity, with a decreasing trend,” reiterated Freitas. “At least in some parts of the country we've already been at the peak.

“But there may always be a second wave: all that is needed is for a drastic change in the climate and the virus," she warned.