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Influenza A H3N2: Types, symptoms, severity, risk factors, treatment & more

Dr. Swati Kaktikar

4 Min Read

Fast Check Fact Checked

Influenza H3N2 is a subtype of the influenza A virus that has been making headlines in national news due to a rise in reported cases in India. It is a type of flu virus that can cause respiratory illness in humans. Like other influenza viruses, H3N2, too, spreads easily from person to person through droplets when an infected person talks, coughs, or sneezes, with coughs lasting for more than a week.

It is important to note that while H3N2 is a newsworthy topic, it is not a new virus. In fact, it has been circulating in the human population for many years and is one of the most common strains of the influenza virus. However, the virus can mutate and evolve, making it difficult to predict and control the spread of the disease.

Let’s now take a closer look at the A H3N2 flu subtype in this article.

Table of contents:

What is flu type A H3N2?
- Subtypes of Influenza A Viruses:
What are the symptoms of the H3N2 variant?
How severe is H3N2 flu?
Who will likely develop complications from the A H3N2 subtype flu virus?
What causes the H3N2 virus?
Prevention of Seasonal Influenza
Treatment
Conclusion

What is flu type A H3N2?

Globally, there are four types of seasonal influenza viruses. They are

Influenza A
Influenza B
Influenza C
Influenza D

While influenza A and B cause severe respiratory illness, type C causes only mild infections.

Influenza D, on the other hand, only infects animals and isn’t known to cause infections in humans.

Subtypes of Influenza A Viruses:

Influenza A viruses are further classified into various subtypes based on the combination of two proteins found on their surface: hemagglutinin (H) and neuraminidase (N).

As of date, there are 18 known subtypes of H and 11 known subtypes of N. Different combinations of these H and N subtypes can result in different strains of influenza viruses* — such as H1N1, H2N2, or H3N2 — which currently infect the Indian population.

What are the symptoms of the H3N2 variant?

The symptoms of seasonal H3N2 influenza can range anything from mild to severe and may include the following:

Fever
Cough
Sore throat
Runny or stuffy nose
Body aches
Fatigue
Headache
Chills
Vomiting and diarrhea (more common in children)

How severe is H3N2 flu?

According to Viral Research and Diagnostic Laboratories (VRDL), the body responsible for collecting samples and information from patients suffering from Severe Acute Respiratory Infections (SARI), it was found that this (H3N2) subtype caused more hospitalizations than the other subtypes. The most common symptoms reported were fever and cough. Most severe cases had breathing difficulties, pneumonia, and seizures, and some required oxygen therapy.

Who will likely develop complications from the A H3N2 subtype flu virus?

The following groups of people are at higher risk than others.

Children under two years old (especially infants under six months)
Adults aged 65 years or older
Individuals with asthma
Individuals with neurologic and neurodevelopmental conditions
Individuals with blood disorders (such as sickle cell disease)
Individuals with chronic lung disease (such as COPD and cystic fibrosis)
Individuals with endocrine disorders (such as diabetes mellitus)
Individuals with heart diseases
Individuals with kidney diseases
Individuals with liver disorders
Individuals who are obese (BMI ≥ 40)
Individuals with weak immune systems
Individuals who have had a stroke
Pregnant people and those up to 2 weeks after the end of pregnancy

What causes the H3N2 virus?

The H3N2 subtype is caused by genetic mutations in the virus’s RNA. Influenza viruses are known to mutate frequently, which makes it difficult to predict and prevent outbreaks.

The H3N2 subtype is believed to have originated from a bird virus and was first identified in humans in 1968. Since then, it has been a cause of seasonal influenza outbreaks around the world*.

Prevention of Seasonal Influenza

Vaccination is the best preventive measure to stay protected from the seasonal influenza virus. The flu vaccine is intended to shield against the predominant strains of influenza viruses that are anticipated to spread during the approaching flu season.

Other preventive measures include

Avoiding close contact with infected individuals
Personal and hand hygiene
Wearing masks when stepping outside
Avoid touching your eyes, nose, and mouth
Maintaining social distancing and, most importantly,
Staying home when sick or infected with this virus

Treatment

If you are experiencing symptoms of influenza, it is essential to take immediate action to manage your symptoms and prevent the spread of the virus.

Drinking plenty of fluids, such as herbal tea, water, and broth, is also crucial. Fluids can help keep you hydrated, which is important when sick. They can also help loosen mucus and phlegm, making it easier to cough up and clear your airways.

Since influenza is a viral infection, taking antibiotics will not be of any use unless you have a bacterial complication. Antibiotics are only effective against bacterial infections and will not work against viral infections. Therefore, you should avoid taking antibiotics unless advised by your doctor.

You should seek medical attention immediately if you experience shortness of breath, wheezing, chest pain, or any other severe symptoms.

Conclusion

The H3N2 subtype is a highly contagious virus found to cause severe respiratory illness and hospitalizations than other influenza A subtypes. But there’s no need to panic; not everybody who is infected will be hospitalized. But if you are someone at high risk for complications from H3N2 (as mentioned above in one of the sections), you should take all precautions, such as maintaining good hand hygiene, wearing masks, stepping out only when required, etc.

It’s also important to seek medical attention immediately if you experience severe symptoms such as breathlessness or chest pain. You can contact one of our doctors available online, and we’ll be more than happy to help you.

Also, feel free to check some of our other telemedicine services online — we provide online doctor consultations, medicine delivery services, at-home lab tests, radiology scans, and more.

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