Influenza Cases in Italy: A Slight Decline, but Experts Warn of Possible Underestimation
According to the latest RespiVirNet surveillance report from the Higher Institute of Health (ISS), Italy has seen approximately 803 thousand new cases of acute respiratory infections, including influenza, in the week from December 29 to January 4. This translates to 14.1 cases per 1,000 patients, a slight decrease compared to the previous week, which reported 14.5 cases per 1,000 patients. Since the start of surveillance, a total of around 7.5 million cases have been registered.
Age Group Incidence and Regional Variations
The highest incidence of influenza is observed in the 0-4 age group, with approximately 37 cases per 1,000 patients. The intensity of the influenza outbreak varies by region, with Campania, Sicily, and Marche experiencing very high to high intensity, while Veneto, Emilia Romagna, Tuscany, Lazio, Abruzzo, Puglia, and Umbria are seeing medium intensity. The remaining regions have low intensity.
Experts from the Infectious Diseases department of the ISS note that the decline in the curve of influenza cases in recent weeks appears to be more pronounced than in previous years. However, they caution that the data may not reflect the real incidence and circulation of influenza viruses due to a possible reduction in visits and data transmission during the Christmas holidays. The positivity rate for influenza in the community was 17% in the first week of January, while in hospital settings it was 40.5%.
Severe and Complicated Forms of Influenza
Surveillance of severe and complicated forms of influenza reveals a number of cases similar to the same week in the previous season. The most prevalent subtype among severe forms is A(H1N1)pdm09, while the most widespread form of influenza in the community is attributable to the A(H3N2) virus. Notably, the majority of cases of severe and complicated influenza concern unvaccinated individuals.
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