Swine Flu Accounts For 98% Of Tested Cases In India, No Deaths: ICMR

The H1N1 swine flu virus represents 98% of all tested influenza cases in India, the Indian Council of Medical Research (ICMR) stated, according to PTI.

The ICMR informed that no deaths have been reported from the H1N1 subtype so far this season.

"Our surveillance network has shown about 98% of the cases that are tested are of H1N1; however, there is no need to panic as there is no shift in the seasonal flu pattern that we normally see," Rajiv Bahl, director-general of the ICMR, told PTI.

India typically experiences two seasonal flu peaks during the monsoon and winter months.

Vaccine Barriers and Spread

Flu shots remain rare in India, where less than 2% of the population has ever received a flu vaccine.

The shots are cost-prohibitive, ranging from Rs 2,000 to Rs 4,000 per dose.

With a moderate reproduction number of 1.3 to 2.8, the virus spreads rapidly in the absence of herd immunity.

In contrast, almost half the US adult population receives an annual flu shot, the US Centers for Disease Control and Prevention stated.

Hospital Admissions and Surveillance

"Some cases are severe, but the number is not unusually high...the worst (in terms of infections) is yet to come," Bahl said. He added that while infections have risen over the past few weeks, severe cases requiring hospitalisation remain low. "We can never know when the peak is going to hit until the number of cases start plateauing and then coming down. So far, the trend shows the number of infections is going up," Bahl said.

Hospitals report an uptick in respiratory admissions, though the situation remains manageable. "The number of admissions of respiratory cases is high, but these are people who suffer from some form of co-morbidities. Not all need admission," Sumit Ray, medical superintendent at Holy Family Hospital in Delhi, said, adding that patients are recovering.

To monitor these trends, the ICMR maintains an active surveillance network of 23 sentinel hospitals across the country. Additionally, 73 labs test at least 25 samples each week of severe acute respiratory infection (SARI) and influenza-like illness (ILI) to identify circulating pathogens.

Circulating Strains and Vaccines

The circulating strain is identified as Influenza A (H1N1) pdm09, specifically the A/Missouri/11/2025-like virus. This strain belongs to clade 6B.1A.5a2a, subclade D.3.1.1 and has been in circulation since 2025.

The ICMR confirmed that these circulating strains match the vaccine strains recommended by the World Health Organisation for the Northern Hemisphere. Based on these recommendations, pharmaceutical companies manufacture annual vaccines to combat seasonal outbreaks.