New Delhi: Delhi-NCR is witnessing a sharp rise in viral infections, as the H3N2 strain of influenza A emerges as the dominant virus this season. A recent survey conducted by Local Circles covering over 11,000 households revealed that 69% of families have reported at least one member showing symptoms such as fever, cough, sore throat, and respiratory discomfort. Compared to March 2025, when around 54% of households experienced similar symptoms, this surge marks a significant escalation, prompting public health experts to raise the alarm.
Medical professionals and virologists have identified H3N2 as the primary culprit behind this outbreak. Unlike typical seasonal flu, this year’s cases appear more severe, with patients experiencing prolonged fevers, reduced responsiveness to over-the-counter medications, and increased hospitalizations, particularly among vulnerable groups such as children, older adults, pregnant women, and individuals with chronic illnesses. Delhi’s dense population, coupled with a high prevalence of co-morbid conditions like diabetes, respiratory disorders, and heart disease, alongside extended monsoon conditions, has further amplified the risk of rapid viral transmission.
Understanding H3N2
H3N2 is a subtype of the Influenza A virus, classified based on surface proteins haemagglutinin (H) and neuraminidase (N). The H3N2 strain has a history of seasonal circulation, evolving year by year and affecting human populations differently. Those with weakened immune systems or chronic health conditions are particularly susceptible, often experiencing more intense symptoms and complications such as pneumonia or the worsening of underlying conditions.
Differentiating H3N2 from COVID-19 and Common Cold
While H3N2, COVID-19, and the common cold are all viral illnesses, they differ significantly:
Virus Type: H3N2 is an influenza A virus; COVID-19 is caused by SARS-CoV-2, and the common cold is typically triggered by rhinoviruses or adenoviruses.
Onset of Symptoms: H3N2 usually appears 1–4 days post-exposure, COVID-19 may take 2–5 days or longer, and common cold symptoms develop gradually.
Symptoms: H3N2 commonly causes sudden fever, chills, severe body aches, headache, sore throat, and fatigue. COVID-19 shares some symptoms but often includes loss of taste or smell and can lead to severe respiratory distress. The common cold is generally milder, involving sneezing, runny nose, and mild sore throat.
Duration: H3N2 symptoms last 5–10 days, with cough and fatigue sometimes lingering; COVID-19 varies widely, and a common cold typically resolves in 3–5 days.
Key Symptoms to Watch
Residents are advised to monitor for:
• High fever (38–39°C) with chills
• Persistent cough and sore throat
• Severe fatigue and body aches
• Headache and nasal congestion
• In children, nausea, vomiting, or diarrhea
• Fevers lasting more than 5–7 days and lingering cough
Seek immediate medical attention if there is difficulty breathing, chest pain, bluish lips or face, confusion, or inability to retain fluids.
Preventive Measures
To curb the spread of H3N2, experts recommend:
• Frequent handwashing with soap and water for at least 20 seconds
• Wearing masks in crowded or poorly ventilated areas
• Covering mouth and nose when coughing or sneezing and discarding tissues safely
• Isolating sick family members and avoiding close contact
• Ensuring proper ventilation at home
• Maintaining good nutrition, hydration, and rest
• Considering seasonal influenza vaccination, especially for high-risk groups
Medical Consultation and Treatment
Consult a doctor if symptoms persist beyond 3–4 days, worsen, or involve breathing difficulties. Treatment options include:
• Prescription antivirals like oseltamivir, most effective if started early
• Fever reducers such as paracetamol
• Cough medicines, as advised
• Supportive care with rest, hydration, and nutrition
• Hospitalization and oxygen support in severe cases
Home care strategies include isolation, using steam inhalation or humidifiers for congestion, keeping separate utensils and bedding for the sick, and regular disinfection of frequently touched surfaces.
With nearly seven out of ten households in Delhi-NCR affected, the H3N2 outbreak is a critical public health concern. While many cases are expected to recover with proper care, high-risk populations must remain vigilant. Early action, awareness, and preventive measures are essential to contain this seasonal influenza surge and reduce complications.
Disclaimer: The information provided in this article is for general awareness purposes only and should not be considered medical advice. For accurate diagnosis, personalized guidance, or treatment, please consult a qualified healthcare professional. Always follow the instructions of your doctor or local health authorities.