epidemic 2025-26, symptoms, duration, contagion

Respiratory viruses are return since September. According to the Sentinelles monitoring network, over the week of September 15 to 21, the incidence rate of these infections (including Covid, flu, RSV) “is increasing and is at a level of activity similar to those usually observed during this period”. The last flu epidemic ended in February 2025. It lasted 3 months, “a longer than average duration and significant severity in all age groups but particularly among those under 5 and over 65” according to Public Health France. 3 million people consulted a local doctor for influenza-like illness. The flu caused 29,000 hospitalizations. “The impact of the epidemic was considerable in terms of mortality. On a set of municipalities recording 84% of national mortality, an excess of approximately 14,100 deaths all causes was recorded during the epidemic. Among the death declared by electronic certificate, 4,925 had a mention of influenza.” Last year, three influenza viruses circulated: A(H1N1)pdm09, A(H3N2) and B/Victoria.

What do you call the flu? A flu syndrome?

The flu is a acute respiratory infectionof viral origin, due to a Influenza virus. It is an infectious and contagious diseasewhich is subject to seasonal epidemics, generally observed during the fall and winter. It is different from a flu syndrome which can be due to many other respiratory viruses such as rhinovirus, respiratory syncytial virus… Most of the time mild, the flu can however be serious in fragile people.

What viruses cause the flu?

Influenza viruses are essentially divided into two types: A and Bdividing themselves into two subtypes (A(H3N2) and A(H1N1) pdm09) or lineages (B/Victoria and B/Yamagata). Type A influenza viruses circulate in many animal species (ducks, chickens, pigs, horses, seals, etc.). Influenza viruses type B circulate mainly in humans. Viruses A and B are the cause of seasonal epidemics in humans but only type A viruses have been responsible for pandemics to date, underlines Santé Publique France. To be infected with the flu virus, you must be in contact with someone who already has the flu. Contamination can occur in three ways:

• By air : a sick person projects droplets of saliva into the air, when talking, coughing or sneezing. Millions of viruses then end up in the air, ready to be inhaled and contaminate you.
• By close direct contact : a sick person shakes your hand or kisses you.
• Speak contact with touched objects by a sick person, for example a door handle or a telephone.

What are the typical symptoms of the flu?

• great fatigue
• chills even when you are not cold
• a dry, painful cough
• then comes the fever which can rise to more than 39°c
• aches
• headaches…

In all cases, in the event of a sudden worsening or without improvement in the condition 72 hours after the first symptomsit is absolutely necessary consult a doctor.

Generally during the flu, coughing is dry and painful. Sometimes this dry cough turns into a wet cough. The cough can last up to 3 weeks or more. It is worrying if it is accompanied by persistent fever, difficulty breathing, a change in skin color, or in the case of children, pauses in breathing and choking.

When to get the flu vaccine?

The flu vaccination campaign begins each year on October 15 in France. This campaign is coupled with the COVID-19 vaccination campaign. It targets all people aged 65 and over, people aged over 6 months, suffering from comorbidities with a high risk of serious form of the disease, immunocompromised people, pregnant women, residents in follow-up care establishments or in medico-social establishments regardless of their age, as well as people living in the entourage or in regular contact with people who are immunocompromised or vulnerable to serious forms. of infection, including healthcare professionals. The vaccines available are Vaxigrip Tetra® (Sanofi-Pasteur Laboratory), Influvac Tetra® (Viatris Laboratory) and Fluarix Tetra® (GSK Laboratory). It’s necessary allow approximately 15 days between vaccination and the moment when the body is protected against the flu. There is therefore no need to wait for the first cold weather or the start of the epidemic to get vaccinated.

What is the average duration of the flu?

A tough flu between 3 and 7 days (5 days on average).

What is the incubation time for the flu?

“The incubation time (time between the time of illness and the appearance of symptoms) generally lasts between 24 and 48 hours, but it can extend to 72 hoursrecalls Dr Parneix. However, the patient is contagious, even before the appearance of symptoms and during an average period of 6 days.“

How long are you contagious when you have the flu?

The flu is a contagious disease. The patient can transmit iteven before symptoms appear and during an average period of 6 days” recalls our interlocutor.

There is a rapid diagnostic orientation test (TROD) flu, feasible in pharmacyat the doctor’s office, or in a medical laboratory to screen for influenza A or B viruses (the most common types of viruses during seasonal epidemics). It is possible without a prescription and consists of a sample in the nose and must be done in the 24-48 hours after the first symptoms appear suggestive of the flu (sudden fever above 39°C, headache, body aches, sore throat, cough, extreme fatigue). Attention, “its sensitivity is low in adults, can be at less than 60% between 70 to 90% in children” would like to indicate the HAS. Laboratories have developed combined antigen tests making it possible to detect flu and Covid at the same time. In 15 to 30 minutes, the patient obtains the result. These tests are available over the counter in some pharmacies.

What are the treatments to treat the flu?

• Take some paracetamol to reduce fever, pain and aches.
• There vitamin C is also sometimes recommended to combat fatigue. Likewise, certain foods are particularly recommended to better combat fatigue.
• If necessary, we can supplement with a nasal decongestant and a cough suppressant for dry and stubborn coughs.
• Finally, it is necessary drink plenty of water and rest.

“The flu is caused by a virus and antibiotics are completely ineffective to treat viral diseases, moreover they could deteriorate the good bacteria which the body needs to defend itself from the disease” recalls Dr Pierre Parneix.

• Cough into the crook of your elbow and cover your nose when you sneeze,
• Wash your hands with soap regularly during the day, especially after blowing your nose, coughing or sneezing.
• Blow your nose into a tissue and then throw it in the trash, ideally closed with a lid,
• To carry a surgical mask.
• THE hydroalcoholic gel is also practical, but in the long term it can dry out your hands.
• Ventilate your interior every day for between 10 and 15 minutes to renew the air
• Finally, remember to ventilate the rooms regularly, several times a day: this will eliminate stagnant viruses in the air, through sneezing and breathing.
• Clean germ nests such as door handles, remote controls, phone screens, etc.

Finally, avoid contact with those most vulnerable to the flu virus: pregnant women, seniors, people suffering from a chronic illness or immunodeficient, young children, etc.

Thanks to Dr Pierre Parneix, medical officer of health and hospital public health practitioner (Bordeaux University Hospital).