Influenza 2024, why it doesn’t pass

Influenza 2024, why it doesn’t pass


Influenza and flu-like syndromes: the season is far from over. We are turning towards spring, but the viruses that normally accompany us during the winter are practically all still there. Thus the long wave of the flu, and of the many pathogens that resemble it and that it brings with it, has not ended, so much so that it has led experts to think of a “spring flu”.

The long tail of the flu

So it is This year’s flu has a very long tail. According to the latest report from the sentinel doctors of the Higher Institute of Health, in the week from 4 to 10 March approximately 372,000 Italians were forced to bed by flu-like syndromes, for a total of over 12,644,000 cases since the beginning of the surveillance.
The symptoms are also severe: fever, cough, runny nose, but also vomiting and intestinal disorders. All this, while the ISS bulletin reports that the number of infected people is “stable” compared to the previous week.
The question many are asking now is what is happening: why the flu viruses don’t go away this year. The answer is Massimo Ciccozziresponsible of the Medical Statistics and Epidemiology unit of the Bio-Medico Campus of Rome, that together with Fabio Scarpa of the University of Sassari and to other colleagues he dedicated a study to the evolution of the influenza virus. “The changing climate, with the swing in temperatures it generates, only helps these viruses to remain among us – explains Ciccozzi -. Viruses that are probably also changing something from a genetic point of view. And that is what we are studying”.

Influence in numbers

The latest numbers on influenza and para-flu viruses refer to the week from 4 to 10 March. The incidence is 6.3 cases per thousand assisted (6.4 the previous week). The proportion of flu-positive samples out of the total of those analyzed decreases (4.4% versus 4.8%), but children under 5 remain more affected: in this case the incidence is 18.1 cases per thousand assisted (the previous week there were 19.4).
All Regions record an incidence level of flu-like syndromes above the baseline threshold, except Molise and Basilicata which return to the baseline level. Among the samples that tested positive, 19% were positive for Sars-CoV-2, 18% for RSV (Respiratory Syncytial Virus), 36% for influenza A, 10% for Rhinovirus while the remainder tested positive for other respiratory viruses .

The symptoms that never leave us

Therefore, even in late March, many Italians are dealing with the symptoms brought by the flu, which are not always mild, because the viruses that trigger them can debilitate, give rise to complications, hospitalizations and even deaths. To treat yourself, if you have no other pathologies in progress, just take fever medications and consult your doctor. “The media representation of influenza epidemics, particularly during pandemics, can influence public attitudes and responses – underline the researchers coordinated by Ciccozzi. -. But sensationalism, combined with the unpredictability of the flu, can contribute to increasing the concern of the population in certain seasons or when new strains emerge”.

The case of influenza B

It also has a place in this framework influenza B, which was expected to peak in these days. What are we talking about? The term influenza refers to the disease caused by the influenza virus, but is generally used incorrectly because it is often associated with all those similar diseases caused by other viral respiratory pathogens. The classification of influenza viruses is type A, B, or C based on nucleoproteins and matrix proteins.

Why are we talking about influenza B? Because it is one of the seven genera of viruses that are part of the Orthomyxoviridae family, single-stranded, negative-polarity RNA viruses. They are distinguished from each other by differences in the nucleoproteins and the matrix protein. While Influenzavirus A causes all influenza pandemics and infects humans, as well as mammals and birds, Influenza B affects only humans (and some cases of pinnipeds, particularly seals).

Influenza virus B is often more present in the transition between winter and spring. It mainly affects people with immune defenses that are not yet fully formed or weakened. The first case is that of children and young people, who go to school and therefore in an environment in which viruses circulate more easily; the second involves the elderly.

Why doesn’t the virus go away?

The person who is working on influenza, in the sense of checking whether something is changing at a genetic level, is Ciccozzi. Which, while on the one hand reassuring us that the long flu season still underway will certainly have an end, on the other hand does not hide the fact that we are still looking for answers to some questions. The basic question is: why haven’t the flu and para-flu viruses gone yet this year?
“The swing of the climate, that is, at times it is hotter and colder, favors the flu because it creates the right habitat for it – explains Ciccozzi -. But this flu season will certainly also end as soon as the climate rebalances itself. Viruses are seasonal and try to adapt to climate changes. But from here to saying that they will remain among us all year round there is a big difference. It would mean having a sub-tropical climate in Italy.”

Mutations in the genome?

“We are studying the flu by focusing on the difference in the HA-NA gene segments (the genome is composed of 13,588 bases and is divided into 8 segments, including these two, which code for 11 different proteins), compared in the flu seasons of 2009 and 2023 – concludes Ciccozzi -. We will see the differences and characteristics that will emerge. But, beyond this, I feel like saying that the virus is no longer aggressive. The fact that it persists despite the spring is due to other factors : the flu returned forcefully after three years of Covid; our antibody system was no longer used to it; we were not wearing a mask, which protected us all that time, and not just from the SARS-CoV-2 virus”.


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