Home Health A-Z H3N2 Virus (Influenza A): Symptoms, Diagnosis, Treatment and Spread

H3N2 Virus (Influenza A): Symptoms, Diagnosis, Treatment and Spread

Verified By Apollo Doctors March 22, 2023 30659 0
H3N2 Virus: Symptoms, Diagnosis, Treatment, Spread and Risk Factors
H3N2 Virus: Symptoms, Diagnosis, Treatment, Spread and Risk Factors


INCREASING CASES OF H3N2: Public Health Hazard and Causing Panic!

Lately, there has been a lot of news in the media about the rising cases of the H3N2 Virus. It is affecting a significant portion of the population. Every 2nd person complains of fever, cough, and flu-like symptoms. 

The rise in flu cases has frightened the general public after battling two years of the Covid pandemic. 

Since January 2023, there has been a steady stream of news about this respiratory viral infection, and periodic updates have been provided regarding the Virus’s spread throughout India. On 6th March, Karnataka reported India’s first death from the H3N2 Virus. Upper respiratory infections and fever are both symptoms of the infection, primarily affecting people over 50 years and under the age of 15.

What is the Influenza A H3N2 Virus? 

There are four distinct kinds of influenza viruses that are responsible for the infectious disease known as the flu: A, B, C, and D. The H3N2 subtype of Influenza A is one of several subtypes.

Changes in the H3N2 Influenza virus 

The H3N2 infection is exceptionally infectious and spreads effectively from one individual to another through respiratory droplets. The virus infect other people if an infected person coughs, sneezes, or speaks. Touching contaminated surfaces with your mouth, nose, or eyes can also spread the virus. The influenza A virus subtype H3N2 is responsible for the highly contagious respiratory illness known as H3N2 flu.

  • Mutation: New strains of the influenza virus can emerge due to rapid mutation. Since the H3N2 virus is susceptible to mutagenesis and evolution, predicting the severity of each flu season is challenging.
  • Sensitivity of the host: People who haven’t been exposed to the virus before or whose immune systems are weaker may be more likely to get the H3N2 flu.
  • Crowded living conditions: Schools, nursing homes, and prisons are places where the H3N2 flu is more likely to spread.
  • Seasonal variations: During the winter, when people tend to spend more time indoors and close to others, the H3N2 flu is more prevalent.
  • Travel: The virus can be transmitted from infected travelers to new locations, so H3N2 flu can be spread internationally.

Symptoms of H3N2 influenza:


Being familiar with the symptoms of H3N2 influenza is essential because early disease detection is linked to treatment and prevention.

The following are some of the typical symptoms of an H3N2 seasonal infection:

The viral infection caused by H3N2 influenza can cause a severe cough lasting up to two weeks. H3N2 Flu can cause serious illness and possibly be dangerous for certain high-risk patients, even though most people recover from the fever within a week without needing to be hospitalized. If the symptoms don’t go away or appear to get worse, it’s critical to keep an eye on the patient and seek professional help.

High-risk groups may require hospitalization. If a member of your household is diagnosed with this infection and has comorbid conditions like asthma, COPD, obesity, or heart or lung disorders, this is something to keep in mind.

H3N2 infection Risk Factors:

Some high-risk groups are more susceptible than others. It is recommended that you exercise caution if you or the affected individual  is in such a group:

  1. Pregnant women 
  2. Kids under five years
  3. Older people
  4. Individuals experiencing constant ailments (aspiratory, persistent heart, renal, metabolic, liver, hematologic, and neurodevelopmental conditions.)
  5. People taking steroids, receiving chemotherapy, or having immunosuppressive diseases like AIDS or HIV.
  6. Healthcare workers who are constantly in contact with patients are more likely to spread the illness to vulnerable people.

H3N2 – Method of Spread

  • Individual – to – Individual transmission by respiratory drops

The H3N2 flu infection spreads quickly, particularly in exceptionally crowded regions like nursing homes, workplaces, public vehicles, and schools.

When an infected individual coughs or sneezes, virus droplets are released into the air. The Virus quickly spreads up to a meter and infects those in close proximity by breathing in the droplets once they are in the air.

  • Physical contact is another way the Virus can spread.
  • You could get an infection if you touch a contaminated surface or object.

Diagnosis of H3N2 influenza:

Diagnosis of H3N2 influenza

Most cases are diagnosed clinically; however, during periods of low activity, the infection due to  other respiratory viruses, such as Covid, respiratory syncytial virus, rhinovirus, and adenovirus, can also present themselves as influenza-like illness. This makes it challenging to distinguish H3N2 influenza from other environmental pathogens clinically. Therefore, a respiratory sample and a laboratory diagnostic test will be required to determine the nature of the pathogen.

Tests that your doctor may recommend: 

  • Swabs from the nose or throat for real-time RT-PCR.
  • Test for H2N3 Virus in culture.
  • Testing for the H3N2 Virus with antibodies.

Treatment of H3N2 Influenza:

  • The Indian Council of Medical Research (ICMR) recommended that physicians treat H3N2 influenza primarily with symptomatic treatment rather than antibiotics.
  • If you feel unwell, see a doctor for a diagnosis and treatment. You may be asked to monitor your vital signs and temperature at home if a doctor suspects H3N2.
  • Drink plenty of water and eat well.
  • Along with cough, warm saline gargles and steam inhalation can alleviate ear and throat discomfort.
  • Follow a doctor’s treatment plan; avoid self-medicating or starting antibiotic or antiviral medications  because they may cause side effects and may not even be necessary . However, when it is deemed necessary, your doctor will prescribe antiviral medications.
  • Seek immediate medical attention if a high-grade fever persists, breathing becomes difficult, or the SpO2 drops below 94.

Precautions for preventing transmission 


  • Following respiratory etiquette: Everyone, infected or not, must cover their nose and mouth with a tissue or handkerchief whenever they cough or sneeze. When venturing outside, mask up.
  • Practice good hand hygiene: Individuals should also thoroughly wash their hands with soap and water.
  • Isolate yourself if you feel  unwell.
  • Get vaccinated every year to keep yourself safe.
  • Drink lots of fluids and stay hydrated
  • Avoid touching your mouth and nose with unclean  hands

The following groups should get vaccinated, according to the World Health Organization:

  • Children aged six months to sixty months.
  • Senior citizens over the age of 65.
  • Women who are pregnant 
  • People who have chronic conditions 
  • Healthcare workers 


  • Avoid contacting your nose, mouth, or eyes, particularly while voyaging.
  • Avoid getting too close to people who are sick.
  • Self medicate 
  • Try to stay away from crowded places as much as possible.

Also, avoid the following:

  • Spitting in public places
  • Shaking hands with people
  • Taking medication without consulting a doctor
  • Eating in crowded places while sitting close to other people


H3N2 infection can be hard to contain, particularly in profoundly populated locales, except if great respiratory hygiene is kept up consistently. Get vaccinated on a yearly basis to reduce your risk of infection. Your loved ones, friends, and colleagues, as well as your workplace or educational institution, will all benefit from being made aware of the dos and don’ts.

Verified By Apollo Doctors
At Apollo, we believe that easily accessible, reliable health information can make managing health conditions an empowering experience. AskApollo Online Health Library team consists of medical experts who create curated peer-reviewed medical content that is regularly updated and is easy-to-understand.

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