Published Aug 22, 2026 | 7:00 AM ⚊ Updated Aug 22, 2026 | 7:00 AM
Doctors attributed the spurt in H1N1 cases to the monsoon.
Synopsis: H1N1 infections are rising across several cities, with schools and households emerging as key transmission settings. Doctors say children, especially those with asthma or other chronic conditions, need closer monitoring. While Delhi has reported a sharp increase, experts describe the broader situation as seasonal influenza and urged vigilance, early treatment and prevention rather than panic.
Clarence High School in Bengaluru was closed on 12 August after two staff members tested positive for H1N1. More than 500 influenza-like illness cases had been reported at the school, with two confirmed H1N1 infections among students, raising concerns about transmission in classrooms and other crowded indoor spaces.
Four hundred kilometres south, at a home in Keralam, the same virus takes a smaller, quieter route. A child comes home from school with a cough. Within days, a younger sibling develops fever. By the weekend, a parent joins them. They try paracetamol before finally calling a doctor.
Physicians across the state describe this chain constantly this season: one child carries the infection from the classroom, and the household absorbs it.
“Transmission can occur within families, particularly when an elder sibling or school-going child becomes infected and acts as a source of infection for younger siblings or other family members,” Dr Lijo George, Consultant, Internal Medicine, Apollo Adlux Hospital, Angamaly, told South First.
He suggested that relatives of the affected child wear facemasks and wash their hands often. Those at higher risk, he added, should consult a doctor.
Also Read: Bengaluru school under 15-day surveillance after 500 students fall sick
On Friday, 21 August, the Union Health Ministry said Delhi recorded 1,449 H1N1 cases as of 12 August, against 229 in the same period last year. That marks a rise of more than six times. Sixty-three cases turned up in the capital on 11 August alone.
As of 17 August, Keralam reported a total of 7,421 influenza cases and 88 fatalities for the year driven by the H1N1 (swine flu).
“We are currently seeing an increase in patients presenting with influenza-like illness, including fever, cough, sore throat, bodyache and significant fatigue,” Dr George said. “A proportion of the patients who are tested are also being diagnosed with influenza A/H1N1.”
He warned against reading the confirmed count as the full picture. Most people with mild symptoms never reach a lab.
“Not every patient with flu symptoms is tested, particularly when the illness is mild and uncomplicated,” he said. “Therefore, the number of laboratory-confirmed H1N1 cases represents only part of the actual influenza activity in the community.”
He pointed to other factors behind regional gaps in reported numbers: rainfall, humidity, population density, school terms, travel and the number of lab tests.
“Comparisons between states should not be made solely based on absolute confirmed case numbers,” he opined. “We also need to consider testing rates, hospitalisation trends and the proportion of respiratory samples that test positive for influenza.”
In Hyderabad, Dr Vamshi V, Consultant, Internal Medicine, Gleneagles AWARE Hospital, has also seen an increase in cases.
“During the monsoon season, the combination of high humidity, people spending more time in crowded indoor spaces, and the natural drift of the virus all contribute to a significant uptick in patients coming in with flu-like symptoms,” he told South First.
He calls it a season doing what seasons do.
“I’d call it a seasonal surge. India typically sees two main flu peaks every year, one during the monsoon and one in winter. The severity and the way the virus is behaving fit the classic seasonal pattern we expect,” Dr Vamshi says.
In Bengaluru, Dr Siri BV, Consultant, Internal Medicine, Gleneagles Hospitals, noticed the shift too, though at a smaller scale.
“There has been a slight uptick in patients presenting with fever, cough and other influenza-like symptoms compared with last year,” she told South First. “While the increase is noticeable at the OPD level, it is not a sharp or unusually large rise in cases.”
Also Read: Kerala steps up surveillance after 56-year-old dies of H1N1
Paediatricians have traced much of this season’s spread to schools and buses.
“Schoolchildren between the ages of 4 and 10 years are most commonly affected,” Dr S Indhuumathy Thayammal, Pediatric Consultant, Rainbow Children’s Hospital, Chennai, told South First. “I have seen cases as young as 6 months old having H1N1 infection, wherein the elder sibling acts as a source of infection, with the initial exposure being from classmates in school.”
Children typically arrive with fever, cough, a runny nose, noisy breathing and a drop in appetite, she said. Some develop fast breathing or dehydration that requires closer attention.
“Children with asthma or other chronic respiratory conditions are at a higher risk for complications of H1N1,” she said. “Compromise of the functioning of lung tissue due to H1N1 infection in a child with a prior respiratory illness can precipitate complications like respiratory distress or severe forms of pneumonia, which may need intensive care.”
Dr George spoke about the high-risk children.
“Children below five years, particularly those below two years, are among the groups at greater risk of influenza-related complications,” he said. “Persistent fever, breathing difficulty, poor feeding, unusual drowsiness or worsening symptoms in a young child should not be ignored.”
Dr Vamshi explained why schools accelerate the spread so effectively.
“Schools are essentially hubs for virus transmission. Kids are in close quarters all day, which makes it very easy for droplets to spread. Plus, younger kids often haven’t built up the same cross-reactive immunity that adults have from years of previous exposures, and they tend to shed the virus at higher levels for a longer period of time,” he says.
Not every patient needs a swab. Doctors describe layered approaches that separate mild illness from cases that need urgent care.
Dr Vamshi explained the system he follows.
“Category A, mild: just fever, cough, and body aches. We don’t test these patients; we focus on managing the symptoms at home,” he said. “Category B, high-risk: elderly patients, pregnant women, people with chronic conditions like diabetes or kidney or lung disease, or children under five. We start them on oseltamivir immediately, ideally within 48 hours of symptoms starting. Category C, severe: trouble breathing, chest pain, low oxygen, or confusion. These patients need an RT-PCR test, immediate admission, and oseltamivir right away.”
Dr George stressed that treatment should not wait on a lab result when a patient looks unwell or belongs to a risk group.
“Antiviral treatment should not necessarily wait for a laboratory result in patients who have severe disease or belong to high-risk groups,” he said. “Oseltamivir is most beneficial when started early, preferably within the first 48 hours, although patients with severe or hospitalised influenza may still benefit when treatment is initiated later.”
He named the groups doctors track hardest: young children, older adults, pregnant and recently postpartum women, and people managing chronic lung, heart, kidney, liver or neurological illness, diabetes or immunosuppression.
Dr Siri BV runs a wider net in her own clinic, testing every patient who presents with symptoms rather than sorting first by risk.
“All patients who come to me presenting influenza-like symptoms like fever, cough and other respiratory symptoms are being tested for H1N1,” she said. “The decision to test is taken primarily on the presence of the symptoms rather than testing only the patients with severe illness.”
Doctors flagged one pattern above the rest: a patient improves, then relapses days later.
“If you start to feel better, but then suddenly develop a high fever and worsening cough again, that’s a sign of a secondary bacterial pneumonia,” Dr Vamshi said.
Dr George also described the same scene.
“Another important warning sign is when someone initially appears to recover from influenza but then develops fever or worsening cough again, as this can sometimes indicate a secondary bacterial infection or pneumonia,” he said.
He listed other signals that call for a doctor rather than home rest: difficulty breathing, rapid breathing, chest discomfort, a fever that won’t break, low oxygen readings, extreme weakness, confusion, drowsiness or reduced urine output.
For children, Dr Indhuumathy pointed to fast breathing, lethargy, refusal to eat or drink, reduced urine output and disrupted sleep from repeated coughing fits.
Dr Siri BV has been keeping the threshold simple.
“A person should consult a doctor if they have fever accompanied by severe body aches, are unable to take medication orally, or develop a severe cough,” she says. “These symptoms call for medical evaluation rather than continued self-medication.”
None of the doctors interviewed called this an outbreak. They described a monsoon season moving through classrooms and households faster than the official numbers can capture.
“So there is a need for vigilance, but not panic,” Dr George said. “The focus should be on early recognition of high-risk patients, appropriate use of antivirals, respiratory hygiene, keeping symptomatic children and adults away from school or work, and encouraging influenza vaccination, particularly among people at increased risk of complications.”
Dr Siri has reached the same conclusion.
“The current situation does not appear unusual and is consistent with the seasonal influenza pattern,” she said. “The slight rise in influenza-like illness is something that can be expected during the seasonal period, rather than taking it as an unusual outbreak.”
At Clarence High School, surveillance teams continue screening students. Swab results from NIMHANS remain pending. And in homes across Keralam, Hyderabad and beyond, a child’s cough still moves quietly from one bed to the next, waiting for someone to notice before it spreads any further.
(Edited by Majnu Babu).
