New Delhi: The Indian Council of Medical Research (ICMR) has told the government that the recent surge in influenza cases is being driven by a circulating H1N1 strain, with no new strain detected in the country, according to two officials familiar with the matter.

According to a senior ICMR scientist, who spoke on condition of anonymity, the circulating H1N1 pdm09 influenza virus has been prevalent since 2025. Officials said the strain closely matches those used in the current influenza vaccines recommended for the Northern Hemisphere.

“Scientists have clarified that no new strain of H1N1 has been identified and there is no cause for panic,” the ICMR scientist said. “Seasonal influenza, including H1N1, is mostly self-limiting. Common symptoms include fever, cough, headache and body ache, and most people recover with appropriate care and rest,” the scientist added.

The clarification comes against the backdrop of heightened review measures by the central government. On Friday, Union health minister J.P. Nadda chaired a high-level meeting alongside Delhi health minister Pankaj Kumar on the rising cases of influenza, taking stock of national surveillance, hospital preparedness and testing infrastructure across states.

During the meeting, Nadda assessed the national epidemiological situation, laboratory surveillance networks, and tracking trends for influenza-like illness (ILI) and severe acute respiratory infections (SARI), the Union health ministry said in a statement. He emphasized the need for heightened vigilance, robust surveillance and clinical preparedness across state health systems to identify and manage clusters or unusual surges in respiratory illness.

So far this year, Delhi has reported 2,392 cases of Influenza A—characterized by sudden onset of high fever and sore throat, among others—with the H1N1 strain accounting for nearly three-fourths of the infections. According to figures shared during the review, the national capital has recorded 1,777 H1N1 cases in 2026, while H3 accounted for 138 cases, H1 for 37, and other influenza variants for 440 cases. Beyond Delhi, other states significantly affected by influenza include Karnataka, Maharashtra and Kerala.

H1N1 influenza, commonly known as swine flu, is a contagious respiratory infection transmitted via airborne droplets when an infected person coughs, sneezes or talks. While most infections remain mild, it can lead to severe complications, including pneumonia and acute respiratory distress, particularly in vulnerable populations such as young children, pregnant women, the elderly and immunocompromised individuals.

Reassuring the public, ICMR scientists emphasized that continuous genomic and virological surveillance has not detected any novel mutations.

“However, young children, elderly individuals and people with underlying medical conditions may be at greater risk of complications. If symptoms persist, worsen, or become severe, timely consultation with a doctor is advised,” the second official cited earlier said.

Queries sent to the health ministry spokesperson remained unanswered till press time.

The apex medical research agency underlined that the country’s public health apparatus remains vigilant, noting that “the situation continues to be closely monitored through regular surveillance, and necessary public health measures are being undertaken.”

Highlighting the clinical ground reality, Dr Harpreet Kaur, medical superintendent and head of lab services and the blood centre (transfusion medicine, haematology and cytopathology) at Aakash Healthcare, said: “There has been a definite spike in H1N1 cases across Delhi. At our hospital, we reported 8 H1N1 cases in July, which increased significantly to 25 cases in August.”

“Our hospital is fully prepared to manage the current caseload. Early diagnosis and timely medical care can significantly improve outcomes, and patients should not delay seeking medical attention out of fear,” Dr Kaur added.