H3N2 in India: Why This Flu Strain Is Causing Alarm

H3N2 in India Why This Flu Strain Is Causing Alarm

Sudden surges of fever and respiratory illness are rippling across Delhi-NCR and beyond - and the culprit is H3N2, a subtype of Influenza A. According to a recent Indian Express report, about 69 per cent of households surveyed in Delhi and surrounding areas say someone in their family has experienced viral, flu- or fever-like symptoms.

While many flu seasons involve Influenza A or B strains, H3N2 tends to be more aggressive - and when immunity wanes, or seasons shift, it can hit harder. Below is what experts are saying about its symptoms, risks, treatment, and prevention.

What Exactly Is H3N2?

H3N2 is a subtype of Influenza A virus, distinguished by its hemagglutinin (H3) and neuraminidase (N2) surface proteins.

Like other influenza viruses, H3N2 undergoes frequent mutations (antigenic drift). These small viral changes can make immunity from past infections or vaccinations less effective.

It spreads via respiratory droplets - when someone coughs, sneezes, talks - or via contaminated surfaces. Enclosed, poorly ventilated spaces accelerate its transmission.

Symptoms to Watch For

Because H3N2 overlaps in presentation with other respiratory viruses, distinguishing features lie in severity, duration, and complications. Common symptoms include:

·         Sudden high fever (often with chills)

·         Persistent cough, sore throat, runny or congested nose

·         Body aches / muscle pain, headache, fatigue

·         In some cases, gastrointestinal symptoms (nausea, vomiting, diarrhea), especially in children

·         Difficulty breathing, chest pain, confusion, dizziness  -  these suggest complications and warrant urgent care

One recent case described a 38-year-old software engineer with 104 °F fever, unresponsive to paracetamol, intense cough, and prolonged fatigue - symptoms more severe than a typical seasonal cold.

Who Is at Greatest Risk?

Though H3N2 can infect healthy people, certain groups are more vulnerable:

·         Children and the elderly

·         People with chronic illnesses (e.g. asthma, diabetes, heart disease)

·         Pregnant women

·         Immunocompromised individuals

Because workplaces, public transport, and crowded indoor settings are common in metro areas, younger and middle-aged adults are seeing significant infection rates this season, especially when they continue regular commuting and social interaction.

Diagnosis & Medical Evaluation

Often, physicians begin with a clinical diagnosis based on symptoms, especially during a known outbreak.

To confirm, they may use:

·         Throat or nasal swab tests, such as rapid influenza diagnostic tests or RT-PCR

·         Blood tests, imaging (chest X-ray) in suspected complications

Testing is more likely when patients have severe symptoms or risk factors.

Treatment: What Can Help & What To Avoid

There’s no “magic cure” for H3N2, but supportive care and timely antivirals can reduce severity and complications.

Supportive Measures

·         Rest & isolation  -  avoiding contact with others for at least 5–7 days or until symptoms ease

·         Hydration, warm fluids, soups

·         Symptomatic relief: fever reducers (e.g. paracetamol), lozenges for sore throat

·         Avoid unnecessary antibiotics, unless secondary bacterial infection is confirmed. Antibiotics don’t work on viruses.

Antiviral Medications

For high-risk or severe cases, antivirals like oseltamivir (Tamiflu) may be prescribed - ideally within 48 hours of symptom onset - to reduce severity and duration.

Caution

Because dengue and other febrile illnesses may co-circulate, health providers sometimes delay use of NSAIDs (like ibuprofen, nimesulide) until dengue is ruled out, to avoid bleeding risks.

Seek immediate medical attention if symptoms worsen, or if breathing becomes difficult, chest pain appears, or confusion sets in.

Prevention: How You Can Protect Yourself & Community

During viral outbreaks like this, preventive habits matter as much as treatment. Key tips:

·         Annual flu vaccination  -  get the seasonal vaccine, which often includes coverage against H3N2.

·         Mask wearing, especially in crowded and enclosed spaces

·         Frequent hand washing with soap & water (20 seconds) or use of sanitiser

·         Good ventilation in indoor spaces

·         Avoid close contact with people who are ill

·         Boost immunity: adequate sleep, balanced diet, fresh air, managing stress

Remember

The H3N2 surge across Delhi-NCR and beyond is a reminder that influenza still poses a serious public health challenge. Though many cases are mild, this strain can cause prolonged illness and severe complications - especially in vulnerable groups. The good news: many tools we already know - vaccines, hygiene, early care - are effective defenses.

If you notice flu-like symptoms, don’t ignore them. Stay isolated, consult a doctor, stay hydrated, and consider testing and antiviral treatment if needed. A proactive, informed approach can make the difference between quick recovery and escalation.

Share Your Thoughts In The Comments Below. If You Found This Helpful, Don’t Forget To Share It With Your Friends And Family!