the peak of infections has passed, 7.8 million Italians affected

The peak of the flu season is now behind us, and the number of cases has started to decline. In the first week of the year, there were approximately 980 thousand flu-like syndromes, recording a decrease of approximately 100 thousand compared to the previous week. During the seasonal peak, seven days before, the maximum was reached with an incidence of 18.3 cases per 1,000 inhabitants, an unprecedented value in past seasons. The decline began on New Year’s Eve and from 1 to 7 January the cases of flu-like syndromes decreased by around 100 thousand units compared to the previous 7 days (16.5 cases per 1,000 people).

These data emerge from the bulletin of the RespiVirNet surveillance system of the Istituto Superiore di Sanità, which, in collaboration with the Ministry of Health, also provided updates on the data relating to Covid. It is notable that Covid cases are also decreasing both in numerical terms and in terms of the impact on hospitals.

The season, however, is not over yet and now seems destined to prove to be one of the most intense ever in Italy. From October to today are 7.8 million Italians affected by flu-like syndromes; with this trend we could exceed the 14 million total infections recorded last year, when the season was particularly aggressive.

Peak passed, but circulation still sustained

Anna Teresa Palamara, director of the Infectious Diseases department of the Istituto Superiore di Sanità, comments that both the epidemiological and microbiological data suggest that the peak has been overcome, even if a persistent circulation in the coming weeks is highly probable, favored by the reopening of schools. Palamara states: “We continue to recommend vaccinations for people at risk, still useful in anticipation of the final phase of the season, which will continue for several weeks. It is important to maintain healthy prudence in behavior. We reiterate the invitation to avoid the use of antibiotics, as they are not effective against viral infections, unless indicated by your doctor, and to go to the emergency room only if strictly necessary”.

As reported in the first week of 2024, the incidence dropped to 16.5 cases per thousand assisted, compared to the peak of the previous week, which recorded 18.3 cases (data updated compared to last week due to delays in notifications).

In the first week of 2024, 34% of the samples analyzed by the laboratories belonging to the RespiVirNet surveillance network tested positive for influenza (it was 46% the previous week). Among influenza viruses, type A viruses are prevalent, in particular the H1N1 pdm09 subtype which is the almost absolute protagonist.

Incidence drops among children, only two regions with high intensity

The incidence of flu-like syndromes is showing a marked decrease in pediatric age groups, with greater relevance in children under five years of age, in whom the incidence is now 33.6 cases per thousand assisted (compared to the previous 47.2 in the previous week). At the same time, stability is observed in the adult and elderly age groups. The bulletin warns that, in all Regions with activation of surveillance, there is an incidence level of flu-like syndromes above the baseline threshold.

The document underlines that there are now only two Regions in which the “very high” intensity threshold of the incidence has been reached: Abruzzo and Sardinia. Antonino Bella, responsible for the RespiVirNet epidemiological surveillance and editor of the epidemiological bulletin, comments: “Although making predictions on the progress of the season is always difficult, the significant decline observed suggests that the peak may have been reached. However, it is not excluded that upward fluctuations may occur, especially in children, due to the reopening of schools.”

Sharp decline in Covid cases

During the week between 4 and 10 January, a significant decline in Covid cases was observed in Italy, with a total of 20,945 new positives, recording a negative variation of 45.9%. The number of deaths also decreased, with 355 deaths recorded in the same period, highlighting a negative change of 4.3% compared to the previous week. Furthermore, the impact on hospitals has reduced, with the employment rate in the medical area as of January 10th equal to 8.2% (5,131 hospitalized patients), compared to 10.1% (6,320 hospitalized patients) on January 3rd. On the same date, the occupancy rate in intensive care was 2.4% (213 hospitalised), compared to 2.8% (246 hospitalised) on 3 January.

Francesco Vaia, General Director of Health Prevention at the ministry, comments on the week’s data by stating: “The indicators show a further reduction in the spread of Covid, also reflected in the decrease in the occupancy rate of hospital facilities, both in the medical area and in intensive care . This result must be consolidated, and the invitation is to continue to protect the most vulnerable through vaccination, which can be received at the same time as the anti-flu vaccination, which is particularly important considering the trend of recent weeks”.

Good news on the vaccine front

In Italy, up to now, they have almost been administered 9.5 million doses of influenza vaccine, with coverage of the over 65 population standing at 45%. Francesco Vaia, director of Prevention at the Ministry of Health, said: “We expect, by the end of the season, to reach the levels of the previous season.” Meanwhile, there has been some good news on the vaccine front.

According to research coordinated by the Ministry of Health of the State of Alberta, Canada, and published on Eurosurveillance, vaccination this season is 61% effective in preventing influenza caused by the A/H1N1 virus, which is the strain dominant. However, notable differences are observed between age groups. The maximum effectiveness, equal to 74%, was recorded in children aged between 6 months and 9 years, while it was lower, of 57%, in individuals over 65 years of age. Protection against other viruses included in this year’s vaccine was 49% against the A/H3N2 virus, which dominated last year, and 75% against influenza B viruses.

The situation in the Regions

The weekly incidence is decreasing in most Regions/Autonomous Provinces. In the Lazio, the highest incidence was recorded, equal to 61 cases per 100,000 inhabitantsWhile the lowest was reported in Sicily, with 5 cases. This decreasing trend involves all age groups. The median age at diagnosis is 60 years, showing a slight increase compared to previous weeks.

It should be noted that the most vulnerable age group is that of the elderly, with the highest hospitalization and mortality rates in subjects over 90 years of age, who also have the highest weekly incidence rate.

As regards the variants, according to the sequencing data available in the national I-Co-Gen platform, the JN.1 variant currently represents the most widespread, with a proportion of 49.2% in the consolidated sampling week (18-24 December 2024). Furthermore, the co-circulation of viral strains attributable to XBB is confirmed, with a particular mention for EG.5, which represents 27.3% of the variants, albeit with decreasing values.