Italy: respiratory infections continue to decline, but 720,000 new cases still estimated in one week

National surveillance data confirm a steady downward trend in acute respiratory infections, although the overall burden remains high. The latest update from Italy’s RespiVirNet system shows a sustained decrease compared with late December peaks, while highlighting continued intense viral circulation among the youngest age groups.

Overall epidemiological picture

Between 12 and 18 January, the overall incidence of acute respiratory infections in the community reached 12.7 cases per 1,000 assisted individuals, down from 13.3 the previous week. An estimated 720,000 new cases were recorded, confirming a slowing trend but still reflecting substantial circulation.

Since the start of seasonal surveillance, total estimated cases have reached approximately 9.2 million, underlining the scale of the current respiratory season.

Children aged 0–4 remain the exception

Incidence is decreasing across almost all age groups, with one notable exception. Among children aged 0–4 years, incidence increased again, reaching around 33 cases per 1,000 assisted individuals. This confirms that young children remain a key driver of viral transmission at this stage of the season.

Regional differences

Viral circulation intensity is classified as very high in Basilicata, Campania and Puglia, high in Sardinia, medium in Molise and low in most other regions. The Autonomous Province of Trento has returned to baseline levels. Comparisons with previous seasons remain complex due to changes in case definitions.

Influenza activity and severe cases

Influenza positivity reached 29.9% in the community and 31.9% in hospital settings. Severe and complicated influenza cases are decreasing compared with the same period last season, with A(H1N1)pdm09 remaining the most frequent subtype among severe cases, predominantly affecting unvaccinated individuals.

Virus characterization

In both community and hospital surveillance, A(H3N2) viruses predominate over A(H1N1)pdm09. Sequencing analyses show that H3N2 subclade K is currently dominant, while all H1N1pdm09 viruses belong to subclade D.3.1, aligned with vaccine strains. No unsubtypable influenza A viruses suggesting avian strains have been detected.

Prevention and targeted care

Despite the downward trend, targeted medical assessments and preventive measures remain essential, particularly for young children, older adults and people with chronic conditions. Early diagnosis, influenza vaccination and timely specialist evaluation continue to play a central role in limiting complications and hospital pressure.