H1N1 cases on the rise, experts say no cause for alarm

Several States are recording a spike in H1N1 cases, among other influenza-like illnesses, viral fevers, and respiratory tract infections. Experts say there is no cause for alarm, but advise that children with asthma and other chronic conditions might require special intervention.

The H1N1 virus, commonly known as swine flu, is a subtype of influenza A, and can cause respiratory illness, with symptoms including fever or chills, cough, sore throat, a runny or blocked nose, headache, tiredness, and muscle or body aches. In some cases, patients may also experience vomiting and diarrhoea.

Six times more cases

Delhi has recorded a sharp rise in H1N1 cases, with over 1,300 infections reported this monsoon season — nearly six times higher than the same period last year.

The national capital had recorded 1,344 H1N1 cases by early August, compared with 229 cases during the corresponding period last year. Government hospitals have set up separate isolation wards, and health officials have urged vulnerable groups, including children and older adults, to take extra precautions. Special wards have been set up at hospitals to manage the surge in cases.

A Brihanmumbai Municipal Corporation (BMC) official also said cases had gone up compared to last year, with Mumbai recording 309 cases between June 1 and August 15 this year, compared to 72 cases during the same period in 2025.

Limited testing

Bengaluru doctors say they are seeing a noticeable rise in influenza-like illness, viral fever, and respiratory tract infections among children. Doctors have also confirmed H1N1 cases, though testing is restricted to children with severe or persistent symptoms and those with severe acute respiratory illness.

At the State-run Vani Vilas Women and Children Hospital, paediatrics head Chikkanarasa Reddy P.S. said respiratory complaints and fever account for nearly 80% of the daily paediatric out-patient load, so only children with more aggressive symptoms are being tested. In Bengaluru’s Clarence High School alone, over 500 cases of influenza-like illness have been reported, with two confirmed cases of H1N1 among students, sparking concerns about transmission in classrooms and other crowded indoor settings.

At the Indira Gandhi Institute of Child Health, director Narendra Babu said the hospital was seeing a steady flow of viral fever cases and confirming around two to three H1N1 cases a day among those tested.

Private sector paediatricians are reporting a sharper rise. Vikas Satwik, senior paediatrician and neonatologistat Motherhood Hospitals, said school-going children account for a substantial share. Sujatha Thyagarajan, lead and head of paediatric intensive care and paediatric emergency at Aster Women and Children Hospital, said H1N1 and other influenza A infections were rising earlier than the usual seasonal pattern.

‘Early testing needed’

In Chennai, J.K. Reddy, a senior paediatrics consultant at Apollo Children’s Hospital, said they have been seeing cases of H1N1 among children for the past two weeks, with a slight rise in cases this week. He advised that children suspected of having influenza should be tested within 24 to 48 hours of developing symptoms. Anti-flu drugs are more effective if started in the first few days of fever. Government doctors also confirmed they are seeing patients with symptoms of flu-like illness, but since routine testing for H1N1 is not conducted at government hospitals, it is difficult to classify them.

Janani Sankar, medical director at the Kanchi Kamakoti CHILDS Trust Hospital in Chennai, said: “Most of the children are managed as outpatients. Some of them with extreme fatigue, severe body pain, and lack of oral intake needed hospitalisation. We are yet to see children with H1N1.”

Ravinder Nayak, Telangana’s Director of Public Health and Family Welfare, said the number of H1N1 cases in the State was lower than in the corresponding period last year. Vijay Kumar, superintendent of Niloufer Hospital, Telangana’s premier State-run tertiary care centre specialising in maternal, neonatal, and paediatric medicine, said the hospital had seen an increase in outpatient consultations for viral fevers from June to August, but there has not been any significant rise in H1N1 or influenza cases so far.

Annual flu vaccines for elderly

Influenza A has been rampant in Kerala for the last three months. Cases began to spike in May, with 526 cases and six deaths, and increased through June (2,050 cases, 26 deaths) and July (2,899 cases, 31 deaths). There have been 1,476 cases and 21 deaths reported so far this month, till August 17.

Cumulatively, there have been 7,421 cases and 88 deaths caused by influenza in Kerala this year, with almost all the fatalities seen in people over 50 years of age.

Public health experts in the State have been urging the government to invest in annual flu vaccinations for the elderly so that, apart from reducing mortality, senior citizens are saved from frequent hospitalisations and high out-of-pocket expenditure on health.

(With inputs from Bindu Shajan Perappadan in Delhi, Snehal Mutha in Mumbai, Afshan Yasmeen in Bengaluru, Serena Josephine M. in Chennai, Siddharth Kumar Singh in Hyderabad, and Maya C. in Tiruvananthpuram)

Published – August 18, 2026 10:24 pm IST