For many Delhi residents, illness begins this time of the year with symptoms easy to dismiss as seasonal sickness: a cough that refuses to go away, a sore throat, body aches and a high fever that lasts for days. But this year, doctors and hospitals across Delhi are seeing more of these patients test positive for influenza, particularly H1N1 (swine flu).

Delhi has reported 2,308 H1N1 cases as of August 25, with over 600 additional influenza cases, taking the reported influenza burden to nearly 3,000, according to figures shared by Delhi Health Minister Pankaj Kumar Singh. The government held emergency reviews on Tuesday as the number of infections continued to rise.

The increase is particularly striking when compared with last year. Delhi had recorded 229 H1N1 cases during the corresponding period in 2025. By August 20 this year, the number had already reached 1,777, nearly eight times the 2025 figure for the same period, before rising further to 2,308 by August 25.

Bengaluru, Mumbai and Chennai have also reported increased influenza activity this monsoon, suggesting the rise is part of a broader seasonal pattern across several major cities.

Delhi hospitals prepare as OPDs see more flu patients

At Lok Nayak Jai Prakash Narayan Hospital (LNJP), a dedicated ward has been designated for influenza cases. The ward has seven beds, including two ventilator beds. Dr Satyajit Kumar, Head of the Department of Accidents and Emergency, said the hospital was prepared for a rise in admissions and that it had not seen any severe cases so far.

Additionally, Kumar noted that should the need arise, the hospital has also earmarked a 70-bed facility on its seventh floor, comprising 10 ICU beds and 60 High Dependency Unit beds. 

At the hospital’s OPD, doctors are seeing patients with high-grade fever and cough that persists for several days. A senior resident doctor said patients with moderate symptoms were being treated as outpatients, with testing being ordered where clinically indicated. Testing itself has increased, Kumar said, contributing to the higher number of cases being detected. But he stressed that the rise should not cause panic.

At Ram Manohar Lohia Hospital, the approach has been similar but without a dedicated H1N1 ward. Dr Ramesh Meena, Associate Professor of Medicine, said beds had been reserved in case admissions increased. “There are no admitted patients with H1N1. All cases of influenza-like illness (ILI) are coming to OPD. They are being treated symptomatically,” Meena said.

In a statement, RML said the number of H1N1 patients requiring admission had remained in single digits and that it was maintaining adequate preparedness for diagnosis and treatment, as of August 25. 

The difference in what hospitals are reporting matters: while OPDs are seeing more flu-like illness and patient numbers have risen sharply, not every patient with fever is being tested. 

Doctors see an uptick, but not necessarily a new or more dangerous virus

Dr Animesh Ray, Additional Professor in the Department of Medicine at AIIMS Delhi, said doctors do not routinely test every person with flu-like symptoms.

“If I am having two or three or four days of symptoms, I may not write tests for that patient,” he said. Testing is more likely when a patient is at higher risk of complications, such as an elderly person or someone with uncontrolled diabetes or heart disease, or when the clinical presentation warrants it. Antivirals may also be considered for patients at higher risk or with more severe disease.

Ray said there had been a definite increase in cases, but cautioned against interpreting the rise as evidence that the virus had suddenly become more dangerous. “There is definitely an uptick in the number of cases,” he said. “These things keep happening every few seasons, few years.” He said some patients were presenting with more fever, diarrhoea and sore throat, with symptoms sometimes lasting longer than expected.

Delhi has witnessed H1N1 surges before, with cases crossing 2500 in 2017 (2835), 2019 (3627) and 2024 (3,151), according to National Centre for Disease Control (NCDC) data.

The Indian Council of Medical Research has also said there is no new H1N1 strain driving the current rise. The strain currently circulating is an H1N1 “pdm09-like virus” that has been in circulation since 2025 and is considered well matched with the vaccine strains recommended for the Northern Hemisphere.

Dr Ravi Shekhar Jha, a pulmonologist at Fortis Faridabad, said his testing has found a high proportion of H1N1 among patients presenting with fever. “About 60-70 percent of fever patients which we are testing are turning out to be positive for the H1N1 virus these days,” he said.

Jha also described a change in the severity of cases reaching his hospital. “Last year, there were very few cases who required ICU admission, but this year, ICU admissions have also gone up, and some patients are experiencing a fall in oxygen level as well,” he said. He added that some patients who recover from influenza are subsequently developing secondary bacterial infections, while people whose asthma or Chronic Obstructive Pulmonary Disease had previously been controlled were experiencing worsening symptoms.

A recent death in Madhya Pradesh has also underscored the concerns over severe illness.

A woman in her 60s from Ujjain who had tested positive for H1N1 died at her home on August 19, a day after leaving a private hospital in Indore, reported Amar Ujala. A report by NDTV noted that the woman allegedly left the hospital against medical advice. The Madhya Pradesh Health Department subsequently ordered an investigation and issued a show-cause notice to the hospital after officials said the case had not been reported to the health department as required under disease-surveillance rules. She had been treated at a private hospital in Indore before returning to Ujjain.

A three-member investigation team is now examining the circumstances of her death. The Indore Chief Medical and Health Officer said the hospital had not informed authorities about the H1N1 case. The case also illustrates why rising case numbers cannot be viewed only through the lens of hospital admissions. 

Flu shots remain underused

Doctors are also pointing to a preventive measure that remains underused in India: influenza vaccination.

Ray said people should be more conscious about preventing transmission, particularly when they develop symptoms. “If I am having symptoms, I would isolate myself. I would not expose other people,” he said, adding that vaccination was an available preventive measure but that there was limited awareness around it.

He added that people should take precautions if symptoms arise. Wearing face masks and using sanitisers, maintaining good hand hygiene, and following proper cough etiquette, such as covering the mouth while coughing, should especially be practised in public places.

The advice comes as health authorities have taken a more cautious position on vaccination. ICMR Director General Dr Rajiv Bahl has said the influenza vaccine available in India can be taken by people who feel they need it after consulting their doctors, while also noting that it is not part of a government recommendation for the general population, reported The Indian Express.

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