Influenza: A Violent Season, to Last Throughout April

The season of “extraordinary and violent” diseases is still underway, in which not only the spread of the influenza virus affects, but also the synetiological disease: a combination that has produced an important effect, both in terms of infection and hospitalization. “If in recent years, these days, the influenza season has been considered closed, this year it will last at least until the end of April – emphasizes Massimo Andreoni, scientific director of the Italian Society of Infectious and Tropical Diseases (CEMIT) – it will be necessary to monitor the situation in order to understand if we are dealing with with unicum or if the current situation risks becoming more and more frequent. This year’s flu season saw the highest number of infections in the last 23 years, according to data from the Istituto Superiore di Sanità (ISS).

“It started earlier, at week 42 and not the usual 48 – explains Claudio Criscielli, President of the Italian Society of General Medicine (Simg) – to reach a high and lasting peak, continuing to stay high throughout the winter period. A slow and gradual decline is now observed, But we are still above the epidemic threshold: if only 5.8 cases per 1,000 population are spoken among adults and the elderly, it is very high for children. The numbers of influenza-like syndromes speak for themselves: at the end of March there was talk of some 13 million citizens infected, a number that is set to rise until the end of April. “However, it was not only the influenza virus that spread – continues Cricelli – especially the A virus, but also many other viruses similar to it: Sars Cov2, respiratory syncytial virus, adenovirus, cold virus.” The recorded complications, which were mainly of the respiratory type and affected mainly the elderly, “point to the fact – and he concludes – that we must increase the rate of vaccination adherence.”

This week the flu season crossed a new milestone: according to the latest InfluNet epidemiological report of the Istituto Superiore di Sanità, with 300,000 infections recorded between March 27 and April 2, the threshold of 13 million cases of influenza-like illness has been crossed since the start of the season. This has never happened since I started monitoring InfluNet. The report depicts the slow slope of the curve: in the past seven days, the infection rate was 5.1 cases per thousand, compared to 5.8 in the previous week. The most pronounced decrease was observed in children: in the 0-4 age group, the incidence was equal to 15.38 cases per thousand; in that period from 5-14 years old up to 6.79; in the 15-64 age group at 4.90; in those over 65 years old to 2.33 cases per thousand. On the other hand, the decrease in the prevalence of influenza viruses is remarkable: of the 661 samples analyzed by InfluNet laboratories, 72 (equivalent to 10.9%) were positive for influenza virus. Last week they were 15.8%.