RespiVirNet

Flu: the season is coming to an end but watch out for the little ones

Palamara (Iss): infections in line with the last two years, peak early but no worsening of symptoms. Vaccines proved effective

by Ernesto Diffidenti

6 March 2026

Sick exhausted girl in scarf is lying in bed wrapped in blanket. Young woman with fever and headache is measuring temperature with thermometer, treated at home. Winter cold and flu concept.

3' min read

Translated by AI

Versione italiana

Key points

Early peak but no serious symptoms
Eurosurveillance reports first estimates of vaccine efficacy

3' min read

Translated by AI

Versione italiana

Acute respiratory infections continue to decrease, which in the week from 23 February to 01 March infected 7.5 cases per 1,000 people. "This year's flu season is going to be of an intensity comparable to the two previous ones," says Anna Teresa Palamara, who heads the Department of Infectious Diseases of the Istituto Superiore di Sanità, "even if for a few weeks we will still have a significant number of cases, especially among the youngest.

According to RespiVirNet data, just published by the Iss, there are an estimated 406,000 new cases in the last seven days, with a total of around 12.6 million flu infections since surveillance began. In practice, one in five Italians has caught the flu. The highest incidence is observed in the 0-4 age group, with about 30 cases per 1,000 patients, but even in this age group there is a slight decrease compared to the previous week (31). The intensity is low in the provinces of Trento and Bolzano, Friuli, Emilia Romagna, Marche, Abruzzo, Campania, Apulia, Sardinia and Basilicata and at baseline in all other regions.

Early peak but no serious symptoms

'From the virological point of view,' Palamara continues, 'the emergence of the K subclade of the H3N2 strain, the so-called 'K variant', has probably led to an earlier peak, as was the case in other European countries, but at the moment there are no signs that it has also had an effect on the severity of symptoms. This is shown, for example, by the hospital flow data, where there has never been a clear preponderance of admissions for this variant. In general, the validity of the vaccination recommendations is also confirmed for this season, with the majority of cases of severe and complicated influenza involving unvaccinated persons, as also proven by the first studies just published'.

Among circulating respiratory viruses, the highest positivity rates were detected for Rhinovirus, VRS, and Metapneumovirus. In the hospital stream, among respiratory viruses the highest positivity rates were detected for Rhinovirus, VRS, and Metapneumovirus.

Eurosurveillance reports first estimates of vaccine efficacy

And the results of the first nine preliminary studies conducted by the researchers of the European IVE group, of which the Iss is also a member, published in Eurosurveillance, are also starting to arrive, according to which 'the efficacy of the flu vaccine used this season was higher than expected, and the data confirm the validity of the recommendations on vaccination in the populations for which it is intended'.

The research, the results of which were used to formulate the vaccine for the next season, analysed data from 16 European countries in total. In some of these, including Italia, the season started early, with the A strain viruses predominating, with the so-called 'K variant' being the most represented. 'This variant is very different from the virus included in the vaccine,' reads the article, 'and this could suggest the possibility that it could bypass the immune protection'. Instead, the efficacy values found by the studies were comparable to those of past seasons. "In a season dominated by influenza A(H3N2), the results of the nine European studies indicate low to moderate efficacy," the authors write, "with immunisation preventing one third to one half of the effects of infection among vaccinated persons. Overall efficacy was higher in children than in adults'.