Spike in swine flu cases reported amid humid, variable weather conditions

Cases of H1N1, commonly known as swine flu, are rising in Delhi-NCR and several other parts of the country as humid monsoon conditions and frequent changes in weather coincide with increased circulation of respiratory infections, doctors have said.

Health experts are reporting more patients with fever, cough, sore throat, body aches and fatigue, with influenza A emerging prominently among respiratory infections being detected at hospitals and clinics.

The rise has also been noticed among children. In Bengaluru, paediatricians have reported an increase in H1N1 infections in recent weeks, while a large outbreak of flu-like illness at a school recently led to hundreds of students staying away from classes and at least two H1N1 cases being confirmed.

Delhi reports sharp rise in cases

Delhi has witnessed a particularly significant increase in H1N1 infections this year. More than 1,300 cases have been reported in the capital in 2026, substantially higher than the corresponding period last year.

Doctors say the actual circulation of influenza can be wider than confirmed case numbers suggest because many people with mild symptoms recover without undergoing specific testing for H1N1.

The monsoon can create conditions favourable for respiratory transmission as people spend more time indoors, often in crowded or poorly ventilated spaces. Rapid changes between hot, humid outdoor conditions and air-conditioned indoor environments may also coincide with increased respiratory complaints.

H1N1 spreads primarily from person to person through respiratory particles released when an infected individual coughs, sneezes, talks or breathes at close range. It can also spread when contaminated hands come into contact with the nose, mouth or eyes.

Children among those affected

Paediatricians have reported increased influenza A infections among children, with schools providing an environment where viruses can spread quickly because of prolonged close contact.

Doctors in Bengaluru have noted H1N1 particularly among younger children, while those with asthma, cardiac conditions, respiratory illnesses or weakened immunity face a greater risk of developing complications.

The recent episode at Clarence High School in Bengaluru brought the trend into focus after more than 500 students were reported absent amid widespread fever, cough and cold symptoms. At least 21 staff members were also absent, while two H1N1 infections among students were confirmed.

The school temporarily suspended physical classes and undertook cleaning and sanitisation measures.

Health specialists have advised parents not to send children with active fever or flu symptoms to school, both to allow them adequate recovery time and to reduce transmission among classmates.

Symptoms can resemble ordinary flu

One challenge in identifying H1N1 is that its symptoms closely resemble those of seasonal influenza and several other viral respiratory infections.

Patients commonly experience fever, cough, sore throat, headache, fatigue, chills and muscle or body aches. Some may also develop gastrointestinal symptoms.

For most otherwise healthy people, the infection remains mild and recovery occurs with rest, hydration and appropriate medical care. However, influenza can become serious in vulnerable patients.

Doctors say difficulty breathing, persistent high fever, severe weakness, dehydration, chest discomfort, confusion or a sudden deterioration after an initial improvement should prompt medical attention.

Young children, elderly people, pregnant women and those with chronic lung or heart diseases, diabetes or compromised immunity are among the groups at greater risk of complications.

Doctors advise vaccination and basic precautions

Health specialists have emphasised that the current rise does not require panic but does warrant greater attention to basic respiratory precautions.

People experiencing flu-like symptoms have been advised to stay home where possible, avoid close contact with others and follow cough and hand hygiene. Wearing a mask can help reduce transmission when an infected person must be around others.

Annual influenza vaccination is also recommended for protection against circulating seasonal flu strains, particularly for people in higher-risk groups.

Doctors have cautioned against self-medication with antibiotics because H1N1 is a viral infection and antibiotics do not treat the influenza virus. Antiviral medication may be prescribed in appropriate cases, particularly when treatment begins early or a patient is at greater risk of severe illness.

With humid conditions continuing and schools, offices and public spaces facilitating close contact, doctors expect respiratory infections to remain a concern through the monsoon period. The emphasis, they say, should remain on early recognition, keeping symptomatic people away from crowded environments and seeking timely medical advice when warning signs appear.