Seasonal flu 2026: symptoms and how to treat it

Seasonal flu 2026 is affecting a great many Italians and is reaching one of its peaks in December. It is an acute respiratory illness caused by influenza viruses. These viruses undergo continuous mutations, giving rise to new strains that can evade the immunity already present in the population. For this reason, there is important epidemiological surveillance. It serves to characterize the circulating viral strains, which is crucial for preparing effective vaccines and for managing public health.

Seasonal flu: the viral strain

It is not possible to specify with absolute certainty the predominant viral strain for the entire 2024 flu season. Information on circulating strains is constantly updated by health surveillance bodies such as the WHO and the ECDC. In general, however, influenza viruses are divided into four types: A, B, C and D. Types A and B are responsible for seasonal epidemics in humans. Type A viruses are further divided into subtypes based on two surface proteins: hemagglutinin (H) and neuraminidase (N). The information available at the end of 2024 indicates circulation of influenza A viruses (H3N2 and H1N1) and influenza B viruses.

Symptoms

Influenza typically presents with the sudden onset of:

• High fever (above 38°C): Often accompanied by chills.
• Dry or productive cough: Persistent and sometimes severe.
• Sore throat: A burning sensation or pain when swallowing.
• Myalgia and arthralgia (muscle and joint pain): Widespread and intense.
• Headache: Frontal or generalized.
• Asthenia (weakness and fatigue): A marked feeling of exhaustion.
• Rhinorrhea (runny nose) and nasal congestion: Sometimes present.

In children, gastrointestinal symptoms such as nausea, vomiting and diarrhea may also occur.

Differential diagnosis

It is important to distinguish influenza from other respiratory infections, such as the common cold or SARS-CoV-2 infection (COVID-19). Rapid onset of symptoms, high fever and intense myalgia are more characteristic of influenza. Rapid diagnostic tests can confirm the diagnosis. The tests can also be done at the analysis laboratories of the Nefrocenter group, which guarantee the accuracy of the results.

Treatment

Treatment of influenza is mainly symptomatic and aims to relieve symptoms:

• Rest: Essential to promote recovery.
• Hydration: Drink plenty of fluids to prevent dehydration.
• Antipyretic and pain-relief drugs: Such as acetaminophen (paracetamol) or ibuprofen, to reduce fever and pain.
• Nasal decongestants: To relieve nasal congestion.
• Antiviral drugs (in specific cases): Neuraminidase inhibitors (such as oseltamivir and zanamivir) can reduce the duration and severity of the infection, but they are generally reserved for patients at high risk of complications.

Complications

The complications of seasonal flu 2026 can be serious, especially in frail people such as older adults, young children, people with chronic diseases or people with weakened immune systems. In fact, the following complications can arise:

• Bacterial pneumonia: A secondary bacterial infection affecting the lungs.
• Bronchitis: Inflammation of the bronchi.
• Sinusitis and otitis media: Inflammation of the paranasal sinuses and of the middle ear.
• Worsening of pre-existing chronic conditions: Such as cardiovascular, respiratory or metabolic diseases.
• Encephalitis: A rare but serious inflammation of the brain.

How the vaccine works and how effective it is against seasonal flu

The flu vaccine is the most effective means of preventing influenza and its complications. Flu vaccines contain inactivated viral strains or virus fragments that stimulate the immune system to produce specific antibodies. These antibodies protect the body from infection if it is exposed to the influenza virus. The effectiveness of the vaccine varies depending on how well the viral strains in the vaccine match those in circulation, as well as on the characteristics of the vaccinated person’s immune system. Nevertheless, vaccination significantly reduces the risk of catching influenza, of developing severe complications and of being hospitalized.

A disease already described by Hippocrates

Descriptions of illnesses with flu-like symptoms go back to ancient times. Hippocrates, in the 5th century BC, described epidemics with acute respiratory symptoms. Throughout history, numerous influenza pandemics have had a devastating impact on the world’s population, such as the 1918-1920 “Spanish flu” pandemic.