What exactly is the flu?
An infectious disease caused by a virus, myxovirus influenzae, an infectious agent which generates an infectious disease, transmissible by the respiratory route, via the spit, or the hands. The flu has a particularity, a very rapid incubation rate. Barely two days after being in contact with a flu patient, you can present the picture of the disease. Cold temperatures favor the survival of influenza viruses, which explains why epidemics occur in winter in temperate climates.
What are the symptoms that will immediately lead to a diagnosis of the flu?
After contact with the virus, the patient will present a brutal picture. A few hours later, he will be exhausted, amorphous, with chills, headaches, fever, aches and respiratory signs: runny nose, sore throat, dry cough. The symptoms that definitely indicate the disease revolve around diffuse pain. You can have pain in your joints, back, shoulders, neck. This is associated with photophobia, difficulty tolerating light. Paradoxically, the patient’s clinical examination shows no abnormality, neither in the lungs nor in the throat, no stiffness in the neck either…
The medical descriptions refer to a “V-shaped picture”, can you explain to us?
Indeed, we have long considered this particularity specific to the flu. The patient has a high fever for two days, then it fades, drops and presto, it starts to rise again. It is the thermal curve which presents a V. V as a virus. In reality, the illness does not last more than five days maximum, I would say between two and four days. If the patient is still ill after five days, this means that there is a secondary infection, with an increased risk.
Why is the flu virus different from year to year?
Because it mutates regularly, when it passes from host to host. It adapts, it evolves. We had the same problem with the Covid-19 coronavirus. The vaccines had to be adapted accordingly. In fact, the virus mutates on its envelope and the immune capacity acquired the previous season disappears. Hence the interest in getting a vaccine every year, since our immune system becomes naive again…
How are vaccines designed? What benchmarks do laboratories use to know the viral mutation of the coming year?
Vigilance has been established for decades on viruses at the global level. The flu is starting to rage in the Southern Hemisphere, which allows us to anticipate the possibility of a mutation. It’s not entirely accurate. This year, we are facing three influenza viruses, but the most dominant is an A virus, which corresponds to the vaccine produced and distributed here since October.
Who are at risk of being hospitalized due to the flu, or of dying?
Statistics from Public Health France show a number of deaths directly linked to the flu, between 8,100 and 14,400. People at risk are the most vulnerable, either because they are elderly or suffering from chronic illnesses. Babies with pathologies are also exposed.
