Influenza is late, but seasonal viruses are increasing: which ones are circulating

The role of temperatures in the spread of influenza

"The cold indirectly favors the transmission of the flu because we spend more time in closed environments, often poorly ventilated, and because certain environmental conditions can facilitate the survival and spread of respiratory viruses. Rain alone does not cause the flu, nor are changes in temperature a direct cause of the infection. To get sick we must encounter a virus", Pregliasco specified, as reported by RaiNews. The mild temperatures of these weeks could therefore influence the timing of the spread of the flu, without however allowing us to predict when the peak of infections will be reached. The mild climate "can change the timing of the epidemic, but does not allow us to predict with certainty when the peak will arrive. It would therefore not be surprising to see an acceleration of infections in the coming weeks. In short, we must not wait to see full hospitals or classes decimated by absences to start protecting ourselves", recommended the virologist.

Which respiratory viruses are circulating

Even if the actual flu takes its time, many people are already dealing with colds, fever and other respiratory ailments. "What we commonly call influenza is actually a set of respiratory infections caused by different viruses, which can give very similar clinical manifestations. At this stage of the year we must consider different protagonists: rhinoviruses, responsible for many colds; seasonal coronaviruses; Sars-CoV-2, which continues to circulate regardless of the season; adenoviruses, parainfluenza viruses and, progressively, the respiratory syncytial virus, particularly important for young children and the elderly", specified the expert. "To these are added the influenza A and B viruses, which can already circulate before the start of the real epidemic phase. Not all flu-like syndromes are caused by influenza.

Rezza: "Reactivate respiratory virus surveillance immediately"

Meanwhile, the epidemiologist Gianni Rezza, extraordinary professor of Hygiene at the Vita-Salute San Raffaele University of Milan, has launched an appeal to reactivate the RespiVirNet respiratory virus surveillance system as soon as possible. As the flu season approaches, "the surveillance of respiratory viruses, the so-called RespiVirNet system, also foreseen in the Pandemic Plan, should be quickly restarted. It is hoped that the lack of the implementing decrees of Premal, the new digital platform of the Ministry of Health, will not create the problems that at the beginning of the summer season led to a delay in the start of the surveillance of arboviruses", he declared to Adnkronos Salute. The Regions, Rezza recalled, "still collect the data and the platform of the Higher Institute of Health is already tested, but the problems relating to privacy put the transmission of granular information at risk, so the problem must be solved - and the special surveillance formalized - from a legislative point of view, possibly in a short time". In summary, "the special surveillance system possible thanks to the collaboration between Regions and ISS, i.e. RespiVirNet, must be activated as soon as possible. This makes the launch of the implementing decrees of the Premal of the Ministry of Health urgent, also to allow the full implementation of the tasks indicated in the Pandemic Plan", he concluded.