H3N2 Flu – How to Treat?

FLU, also known as influenza, is a respiratory disease that annually affects between 5% and 15% of the global population. According to estimates by the World Health Organization (WHO), these infections result in 250,000 to 500,000 deaths each year.

Influenza is a highly contagious viral illness that affects both the upper and lower respiratory tract. Several strains of the influenza virus contribute to its emergence. Transmission occurs mainly through small respiratory droplets that are expelled when coughing, talking or sneezing. Furthermore, the flu can also spread through contact with surfaces contaminated with the virus, which when touched can lead to infection when hands come into contact with the nose or eyes. The flu can be transmitted before an individual is symptomatic and up to 5 to 7 days after infection.

A variant of the influenza virus is H3N2, which over the years has caused concern around the world due to its ability to cause significant seasonal outbreaks. This viral strain poses a serious threat to the respiratory system. Therefore, it is essential to understand the symptoms associated with it and the treatment options available to minimize its impacts on the health of the population.

Belonging to the Orthomyxoviridae family, this viral variant is recognized for its tendency to mutate frequently, which presents a significant challenge for health authorities in terms of prevention and control.

Since their introduction in 1968, H3N2 influenza viruses have undergone an extensive process of genetic evolution and antigenic changes, which has resulted in a series of seasonal epidemics. This is evident in the WHO recommendation of 28 vaccine strain modifications over this period.

Furthermore, H3N2 viruses have also modified their receptor binding characteristics over the last fifty years, now showing a reduced affinity for oligosaccharide analogues present on the cell surface.

H3N2 transmission

H3N2 is transmitted from person to person by droplets expelled when an infected person coughs or sneezes. The virus can also be transmitted through contact with contaminated surfaces.

Transmission occurs more easily in closed environments and crowds. The incubation period is short, 1 to 4 days, and infected people can transmit the virus even before symptoms appear.

H3N2 Flu Symptoms

People suffering from an influenza infection often experience symptoms such as fever, sore throat, cough, nasal discharge, headache, and myalgia. Symptoms of H3N2 flu can range from mild to severe and often appear suddenly.

The fever can be high, often accompanied by chills and sweating. A dry, persistent cough is a typical symptom of H3N2 infection. A stuffy or runny nose is another frequently observed symptom. Additionally, the throat may become irritated and sore. Muscle and joint pains are common. H3N2 infection also causes a feeling of tiredness and generalized weakness.

Acute symptoms usually last for an average of seven to ten days, and the disease tends to resolve itself in most healthy individuals.

In more serious situations, H3N2 flu can trigger respiratory complications, such as bronchitis or pneumonia, especially in risk groups, such as the elderly, young children, pregnant women and people with underlying medical conditions. Groups considered to be highly vulnerable, including those with chronic lung diseases, heart problems and during pregnancy, have an increased likelihood of developing serious complications, which can develop in less than 48 hours from the onset of symptoms.

H3N2 Flu Treatment

Treatment for H3N2 flu aims to alleviate symptoms and reduce recovery time. Key measures include:

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1 – Rest

It is important to rest and avoid exposure to crowded environments to prevent the spread of the virus. Rest helps you conserve energy and allows your immune system to focus on fighting the virus.

2 – Hydration

Drinking plenty of fluids is essential during H3N2 infection. Fever and sweating can lead to dehydration. Therefore, adequate hydration helps prevent this problem, in addition to keeping the airways moister and facilitating the expulsion of mucus.

3 – Medications

Over-the-counter pain relievers and antipyretics, such as acetaminophen, can be used to relieve fever and body aches. However, you must follow the doctor’s or pharmacist’s instructions regarding dosage.

  • neuraminidase inhibitors – Oseltamivir and zanamivir are antiviral medications that work by preventing the replication of the influenza virus. They are most effective when administered within the first 48 hours after symptoms begin.
  • Bronchodilators – Medicines such as salbutamol can be used to relieve coughing and shortness of breath caused by bronchitis associated with the infection.
  • Corticosteroids – In cases of pneumonia or exacerbation of asthma and COPD, corticosteroids can help reduce airway inflammation.
  • Antibiotics – They are only indicated if a secondary bacterial infection occurs, such as bacterial pneumonia, sinusitis or otitis. The most commonly used classes are macrolides, fluoroquinolones and amoxicillin.

4 – Antivirals

In severe cases or in high-risk patients, the doctor may prescribe specific antivirals to combat the H3N2 flu virus. Antivirals such as oseltamivir (known as Tamiflu), zanamivir (sold as Relenza) and peramivir belong to the category of neuraminidase inhibitors and can be used as part of treatment.

These medications aim to block the action of the neuraminidase enzyme, which plays a fundamental role in the influenza virus’s ability to escape host cells and spread through the respiratory tract.

By blocking this enzyme, antivirals limit the release of new viral particles from infected cells, helping to contain the multiplication of H3N2 in the body. It is important to note that these medications are most effective when administered soon after symptoms appear.

Antibiotics have no effect against H3N2 because it is a virus. They are only recommended if a secondary bacterial infection such as sinusitis or pneumonia occurs.

People with severe cases may need hospitalization to receive hydration, supplemental oxygen, and treatment for complications.


Patients with severe H3N2 may need:

  • Monitoring blood oxygen levels through oximetry.
  • Administration of supplemental oxygen if levels are low.
  • Control of hydration and electrolytes through intravenous fluid.
  • Admission to an intensive care unit in very serious cases.
  • Use of mechanical ventilation if there is respiratory failure.


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Prevention is essential to prevent the spread of H3N2 flu. Preventive measures include:

Hand hygiene

Washing your hands with soap and water regularly helps reduce the transmission of the virus.

Avoid contact with people with the flu

Avoiding close contact with sick people and avoiding crowds during flu outbreaks can help lower your risk of infection.

Respiratory etiquette

When coughing or sneezing, covering your nose and mouth with your elbow or a disposable tissue helps contain the virus.


Receiving an annual flu vaccination is one of the most effective approaches to preventing H3N2 infection, as well as its possible complications. Although the flu vaccine does not provide 100% absolute protection, it has the ability to reduce both the severity and duration of symptoms in most individuals.

It is recommended that people with conditions such as lung diseases, diabetes, chronic pathologies, the elderly and children undergo immunization against the flu, as this measure can even avoid hospital admissions.


There is no specific treatment for H3N2 infection. Treatment aims to alleviate symptoms:

  • Rest
  • Consumption of fluids for hydration
  • Medicines for fever and pain, such as acetaminophen and ibuprofen
  • Cough relief medicines

The flu vaccine protects against the main subtypes of the influenza virus that are circulating, including H3N2. It is recommended annually for risk groups such as the elderly, children and people with chronic medical conditions.

Adopting hygiene measures and respiratory etiquette is also important to prevent the spread of the virus. The use of face masks may be considered in outbreak situations.

Source: blogdasaude.com.br

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