Everything You Must Know About H3N2 Influenza

Everything You Must Know About H3N2 Influenza

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Everything You Must Know About H3N2 Influenza

Viral infections are becoming a persistent problem worldwide. Unfortunately, the seasonal transition has created a breeding ground for H3N2 Influenza, which is now an emerging concern in our country. While this viral infection has been reported nationwide since December 2022, the number of cases has significantly increased recently.

On March 3, 2023, the Indian Medical Association (IMA) released an advisory warning that the sudden surge of patients displaying flu-like symptoms, nausea, and diarrhea may be due to the Influenza A subtype H3N2 virus. The IMA also urged medical experts to avoid prescribing antibiotics unnecessarily and instead use symptomatic treatments. Therefore, if you are experiencing persistent cough or other flu-like symptoms, consult the best hospital in Hyderabad as soon as possible to recover quickly and avoid severe complications.

What is H3N2 Influenza?

Influenza A subtype H3N2 is a swine flu infection first detected in 1968 and has since undergone significant genetic changes. Influenza viruses are classified into four types – A, B, C, and D – but the A and B types commonly cause seasonal respiratory illnesses yearly.

According to the Indian Medical Association (IMA), the symptoms of H3N2 infection usually last for 5-7 days, and the fever typically subsides after 3 days. However, coughing and sneezing can persist for up to 3 weeks, so people should not panic.

It is essential to take precautions to prevent the H3N2 outbreak, including getting an annual flu vaccine, practicing good hygiene, and avoiding close contact with people who are sick. In addition, if you experience symptoms, seek medical attention, and follow proper treatment and isolation protocols to prevent spreading the virus to others.

Symptoms of H3N2 Flu

The symptoms of H3N2 influenza are like those of other flu strains but are more severe. Symptoms often emerge one to three days after exposure and can continue for up to two weeks. The following are the most prevalent H3N2 symptoms:

  • High fever (above 100.4°F or 38°C)
  • Dry cough and Sore throat
  • Fatigue
  • Muscle aches and pains
  • Headache
  • Runny or stuffy nose
  • Nausea and vomiting
  • Diarrhea

In severe cases, H3N2 positive can also cause problems such as pneumonia, which can be life-threatening, particularly in the elderly, young children, and people with weakened immune systems.


It is essential to take certain precautions to prevent H3N2 transmission. These include:

  • Wash your hands frequently.
  • Use hand sanitizer if you are traveling.
  • Cover your mouth and nose while coughing or sneezing.
  • Avoid close contact with infected people.
  • Wear a face mask in public places.
  • Stay home if you are sick to prevent spreading the virus to others.
  • Clean and disinfect frequently touched surfaces.
  • Eat green leafy veggies and fruits to improve immunity.

Treatment for H3N2 Flu

The Indian Medical Association has cautioned against the indiscriminate use of antibiotics such as azithromycin and amoxicillin, which can lead to antibiotic resistance. Instead, they advise individuals to seek medical advice before taking such medication. However, specific H3N2 treatments can be carried out to promote faster recovery:

  • Stay hydrated by consuming plenty of fluids
  • Get enough rest
  • Opt for home-cooked meals that are low in spice and fat.
  • Avoid diets that are high in sugar or sodium to prevent dehydration.
  • Use steam to ease chest congestion.
  • Gargle with warm saline water to soothe a sore throat.
  • Take prescribed medications by your doctor.

It is essential to keep calm and avoid taking medications indiscriminately. If you experience any of the symptoms, it is advisable to consult a general physician for a suitable treatment plan.


The best way to prevent H3N2 influenza is to get vaccinated. The flu vaccine is typically available in the fall and is recommended for everyone over six months. The vaccine is formulated yearly to target the virus strains expected to be most prevalent during the upcoming flu season.

The flu vaccine is typically available in two forms: the traditional flu shot and the nasal spray vaccine. The flu shot is an injection that contains inactivated virus particles, while the nasal spray vaccine contains live but weakened virus particles. Both forms of the vaccine are safe and effective, but the nasal spray vaccine is not recommended for everyone, such as pregnant women, young children, and people with weakened immune systems.

Final Words

The H3N2 influenza virus is a highly contagious respiratory infection that can produce severe symptoms and consequences, particularly in vulnerable groups. The best way to avoid catching the virus is to maintain proper hygiene, such as washing hands and avoiding close contact with sick people. Vaccination is the most effective form of prevention. In addition, if infected, it is critical to take appropriate treatment for H3N2 to prevent the virus from spreading, such as staying at home and avoiding contact with others.


How is H3N2 influenza spread?

The highly contagious H3N2 influenza can be passed from person to person via droplets released by an infected individual while coughing, sneezing, or talking. It can also spread if somebody touches their mouth or nose after meeting a virus-infected surface. Flu-related problems are more likely in pregnant women, young children, the elderly, and people with underlying medical conditions.

Is H3N2 swine flu?

H3N2 is an influenza subtype. A virus that can infect people as well as animals, particularly pigs. Although “swine flu” is sometimes used, it also refers to other forms of influenza that affect pigs. H3N2 flu is typically transmitted through respiratory droplets and can produce mild to severe symptoms.

Is H3N2 dangerous?

H3N2 influenza is particularly deadly for vulnerable populations such as young children, the elderly, and individuals with compromised immune systems.

Infections with influenza viruses, including variant viruses such as H3N2v, can cause severe disease in otherwise healthy people. This can lead to consequences like pneumonia, which may require treatment and, in difficult situations, can be fatal.

Is H3N2 the swine flu?

H3N2v is an influenza virus that typically circulates in pigs and can also infect humans. These viruses are known as “swine influenza viruses,” as they commonly infect pigs. However, these viruses are called “variant” viruses when they infect humans.

How long does H3N2 flu last?

H3N2 influenza symptoms can often persist for up to a week, while some may have them longer. Rest, staying hydrated, and using doctor-prescribed medication to relieve discomfort and reduce temperature are the mainstays of treatment.