Rising cases of H3N2 in Delhi-NCR spark concern: key symptoms and risks

Experts urge people to watch for red-flag symptoms like breathlessness and chest pain, seek early medical help, and follow hygiene and vaccination measures

The H3N2 influenza virus is spreading rapidly across Delhi-NCR. Many families are reporting flu-like symptoms, with doctors warning that this strain may be more aggressive than the seasonal flu.

 

H3N2 is a form of the influenza virus that causes respiratory illness. Experts note that its spread typically intensifies during seasonal changes, when immune defences are weakened. 

"H3N2 is an Influenza A subtype with mutations to its hemagglutinin (H3) and neuraminidase (N2) surface proteins. It will cause more virulent illness than seasonal influenza B or H1N1 strains, with higher hospitalization rates, particularly among older adults and children. Its genetic drift is also rapid, so immunity is less long-standing, resulting in recurrent outbreaks," said Dr Tejash D. Gohel, clinical microbiologist and nodal officer Infection control, Lilavati Hospital, Mumbai.

 

Unlike the common cold or regular flu, H3N2, a subtype of Influenza A, is often more severe and tends to last longer, says Dr Mayanka Lodha Seth, chief pathologist, Redcliffe Labs. “If you have been suffering from a cough or cold for more than 48 hours, it’s time to consult your doctor without delay,” says Dr Seth.

 

How does H3N2 spread?

The virus spreads through droplets from coughs and sneezes. Contaminated surfaces and poorly ventilated indoor spaces further aid its spread. 

Key modes of transmission are-

• Direct inhalation of droplets when someone coughs or sneezes
• Touching contaminated surfaces and then the face
• Staying in crowded or air-conditioned rooms with poor ventilation

A LocalCircles survey reported that 69 per cent of households surveyed in Delhi NCR currently have one or more individuals with flu/ viral fever-like symptoms. The main culprit, according to doctors and hospitals, is the H3N2 influenza A virus, which is leading to prolonged fevers, severe respiratory issues, and even hospitalisations.

 

Symptoms you should not ignore

 

• Sudden fever and chills
• Persistent cough and sore throat
• Runny or blocked nose
• Muscle aches, headaches and fatigue
• Nausea, vomiting or diarrhoea (common in children)

 

Warning signs that need urgent attention

• Shortness of breath or wheezing
• Chest pain
• Bluish lips or nails
• Severe weakness or confusion
• Fever that doesn’t subside after several days

“In certain cases, H3N2 can lead to pneumonia, bronchitis, or worsening of existing heart and lung diseases. If you experience a persistent high fever, shortness of breath, or chest pain, seek immediate medical help,” emphasised Dr Manjusha Agarwal, senior consultant, internal medicine, Gleneagles Hospital, Mumbai. In a report by The Indian Express, Dr Agarwal had cautioned that since these symptoms often resemble other viral infections, they should not be ignored, particularly if they last beyond a week.

 

Who is at higher risk of H3N2?

While anyone can contract H3N2, certain groups are more vulnerable to serious complications, shares Dr Rahul Mathur, Internal Medicine Specialist at CK Birla Hospitals, Jaipur. 

• Elderly (>65 years) → Weaker immune responses and higher chance of complications.
• Young children (<5 years, especially <2 years) → Immature immunity, higher risk of severe respiratory illness.
• Pregnant women → Physiological immunosuppression, higher risk of hospitalization.
• People with comorbidities (diabetes, hypertension, cardiovascular disease, COPD, asthma, CKD, liver disease, immunosuppression, cancer) → Increased risk of severe disease and secondary infections.
• Healthcare workers → High exposure risk.

  

Diagnosis of H3N2 and treatment

Tests that your doctor may recommend:

 

• Swabs from the nose or throat for real-time RT-PCR.
• Testing for the H3N2 Virus with antibodies.
• Viral culture (mainly for research/confirmation)

 

Treatment focuses mainly on symptom relief and supporting the immune system:

 

• Adequate rest and hydration
• Fever relief with paracetamol (as prescribed)
• Antiviral medications (if started within 48 hours in high-risk cases)
• Avoiding antibiotics unless prescribed for bacterial co-infection

Symptoms of the H3N2 flu typically last about 5 to 7 days. While the fever subsides within three days, a persistent cough may continue for weeks.  "Homoeopathic remedies are another way to strengthen immunity against the H3N2 virus. The range of homoeopathic treatments for boosting immunity and fighting the H3N2 virus varies widely from person to person. In addition to helping to improve immunity generally, several drugs can alleviate a person's symptoms. These include Arsenicum album, Eupatorium Perfoliatum, Influenzinum, Belladonna, Rhus Tox, Gelsemium and bryonia. Always consult with a qualified homeopath," shared Dr Mukesh Batra, founder and chairman emeritus, Dr Batra's Healthcare.

 

Also read: H5N1 avian influenza detected in Odisha; govt culls over 6,700 birds

 

Prevention: Steps to stay safe

Health experts recommend a mix of personal hygiene and community precautions.

 

• Wash hands frequently with soap and water
• Wear masks in crowded or enclosed spaces
• Maintain well-ventilated indoor environments
• Avoid close contact with sick individuals
• Eat a balanced diet rich in vitamin C, sleep well, and exercise moderately
• Get the seasonal flu vaccine, which includes protection against H3N2

 

What to do if you suspect H3N2 infection

If you develop flu-like symptoms:

 

• Rest, hydrate, and monitor your condition.
• Isolate to prevent infecting family members.
• Avoid self-medication, especially antibiotics.
• Seek medical help immediately if you belong to a high-risk group.

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