Do you know a “master of metamorphosis”? A scholar, some time ago, thus defined the influenza virus. Because it changes. Often by very little, as is happening this year. In other cases there are real profound modifications of the virus. In these circumstances we find ourselves faced with a viral strain substantially new.
This is not the case with the Australian flu, although the AH3N2 virus which distinguishes it certainly presents immunoevasive characteristics, that is, it can be less easy to deal with by the body’s defense system. In recent days there have been the first cases in several regions and even in Genoa there was a hospitalization with neurological symptoms related to the infection.
Because the flu can cause serious complications and that’s why it is It is useful to protect yourself with vaccinationespecially if you are at risk due to age or the presence of chronic pathologies.
Not just AH3N2
In short, the influenza virus tends to present itself with characteristics that are little – or very – different from those of the previous year. Because it must change to survive. In this sense what is defined “Australian” variant of AH3N2 is no exception. But it’s worrying because right on the other side of the planet, in the Australian winter, it proved particularly effective “bad” and with wide diffusion capacity. For this there is great attention, even considering that the first cases arrived substantially early compared to the classic times of spread of the virus, towards the end of December.
It must also be said that there are many viruses in circulation, from parainfluenza viruses to the Respiratory Syncytial Virus (RSV) and obviously to the latest variant of Sars-CoV-2. This is also why there is a risk of exceeding the approximately 14 million cases found last year. And this is why the co-circulation of SARS-CoV-2 and RSV makes this year particularly special vaccination is important to protect the weakest groups. Always remembering that to rule out the possibility of Covid, the classic swab is always helpful.
When it’s “real” flu
As soon as we have a few lines of fever and feel debilitated, perhaps with a headache that doesn’t want to go away, we immediately think “I have the flu”. In reality this is often not the case. Technically we can talk about “real flu” if the symptoms appear in a period ranging from 24 to 72 hours and only if there are three conditions present simultaneously:
- The first is the feverwhich rises rapidly and reaches over 38 degrees
- The second characteristic of influenza is linked to respiratory symptoms, given that the virus has a specific tropism for the cells of this sector of the organism. So the coughthe nasal secretions and the sore throat they often accompany fever.
- Finally, the third characteristic of influenza virus infection, general symptoms such as muscle or joint pain.
In other cases, even if the symptoms may be similar, it is more correct to speak of acute respiratory infections or para-flu syndromes, such as cold.
Who risks more
In general, AH3N2 viruses tend to be particularly difficult to deal with for the elderly and the frail. On the other hand, these subjects are also those who may have the classic “drop” in influenza virus infection that breaks the camel’s back in terms of less than optimal health. Giving rise to complications that can affect various systems starting from the cardiovascular one, so much so that the European Society of Cardiology (ESC) proposes the vaccination with the highest recommendation.
And the same must happen for those who suffer from chronic conditions such as diabetes, respiratory diseases such as COPD, kidney problems with chronic kidney disease as well as many other possibilities.
The phenomenon is particularly worrying of immunosenescence. This term describes the biological aging of the immune system, which is associated with a progressive decline in immunity, poor response to vaccinations, increased exposure to infections (also determined by a greater number of hospitalizations), greater use of antibiotics and increased of paucisymptomatic infections that represent a chronic stimulus to the “proinflammatory” activation of the immune system. Pathogens, such as influenza viruses, therefore find less resistance in subjects over 65 years oldwho are more exposed to contagion and more fragile with respect to the effects.
And Australia, in this sense, certainly represents a problem to be prevented.
A tailor-made vaccination
The World Health Organization (WHO), based on data from the Global Sentinel Influenza Surveillance Network, established the vaccine composition. They exist different types of vaccine to maximize its effectiveness also based on the characteristics of the subject, an effectiveness that certainly manages to avoid the heaviest effects of the disease such as the risk of death although, as is well known, we cannot speak of 100% effectiveness as it is undermined by the fact that the respiratory manifestations are actually due to a cocktail of viruses and only those due to the influenza orthomyxovirus can be protected by the vaccine.
As part of the vaccination composition this year, among other things, only 3 viral strains are expected:
- 2 Type A (one AH1N1 and one AH3N2 updated this year with a Thai variant)
- 1 type B (B/Victoria which however has not been updated); the EMA has in fact suggested “lightening” the formulation by no longer including the B/Yamagata strain as this strain has no longer been in circulation since March 2020 and therefore no longer appears to represent a threat to public health.
The vaccine is at the forefront of flu prevention methods, but it is obviously not the only prevention method we have available. Even if we sometimes forget about them, in fact, they are there simple hygiene rules which should accompany us all year round but which become particularly significant when flu viruses are in circulation. To protect yourself and others from contagion, how wash your hands well, place your hands in front of your mouth and noseor when you cough or sneeze and stay at rest when you are sick to avoid infecting others. For the rest, pay attention to temperature changes when it is very cold. The virus knows how to exploit the imperceptible drop in local defenses that occurs when it is very cold.
What are the characteristics of influenza viruses and what does AH3N2 mean
Influenza viruses are highly contagious and have some characteristics that make them completely different from their “similars”. They are part of the family Orthomyxoviridaetype orthomyxovirus. They have the shape of a sphere, more or less similar to a football although of infinitesimal dimensions compared to it, we are in the order of 80-120 nanometers in diameter. But above all on their external surface they appear “thorny”, because they have some thin protuberances called in scientific terms “spikes”. These structures are fundamental to the the body’s response to the virusfor the activity of drugs and for the development of vaccines. In fact, on these protuberances are found the so-called surface antigens, i.e. hemagglutinins (marked with the initials H) and neuraminidases (marked with the letter N).
These two elements are fundamental for the definition of the virus subtype: in fact, for each influenza strain, a letter is used which characterizes the viral “family” in general terms based on the internal antigens (A, B and C); for type A, the two acronyms H and N, followed by a number specifically distinguish the antigens of the single strain. However, there is no subtype for viruses B and C. Obviously the complex structure of the virus is not limited to its external part. In fact, the viral genetic heritage is present inside it, in the form of ribonucleic acid (RNA).
How to cure the flu
Let’s start with a clear fact. There are no targeted treatments to be applied at random that can directly attack the virus. but fortunately, in addition to the rest and to thelight nutritionwe can counteract the symptoms with drugs defined as symptomatic, such as antipyretics And anti-inflammatories.
Over the days the disorder curve changes and after a few days the picture tends to normalize. They must not be used independently antibioticswhich are only useful for bacterial infections. Your doctor is the only one who can prescribe them. So light nutrition, rest (also to avoid infecting other people with the virus) and an optimal climate at home can help lead to fever. As long as no complications appear. In this case the doctor can advise, case by case, the most correct attitude.
