Even as Delhi’s swine flu caseload so far this year crossed the 2,000-mark on Sunday, the Indian Council of Medical Research (ICMR) has said the outbreak is being driven by a known strain already in circulation and that the numbers across the country are beginning to drop. There is no need to panic, the country’s apex health research body underlined.“No new strain of H1N1 has been identified and there is no cause for panic. The Influenza strains currently circulating are also well-matched with the vaccine strains recommended for the Northern Hemisphere,” the ICMR said.The strain predominantly in circulation across the country, according to the ICMR, at the moment is A/Missouri/11/2025 (H1N1) pdm09-like virus strain, part of clade 6B.1A.5a2a, subclade D.3.1.1 — a lineage that has been in circulation since 2025.A scientist from the ICMR told The Indian Express, “Data shows that around 70% of all respiratory infections in the last week in the Capital were caused by H1N1 virus. It shows that H1N1 has been in circulation and causing a high number of infections over the last four to five weeks with the numbers slowly going down over the last two weeks. The data for the current week is not yet available.”Seasonal influenza, including H1N1, is “mostly self-limiting”, scientists said. “Common symptoms include fever, cough, headache and body ache, and most people recover with appropriate care and rest,” said the ICMR scientist while also cautioning that “young children, elderly persons and individuals with underlying medical conditions” may be at greater risk of complications.Timely consultation with a doctor, if symptoms persist, worsen or become severe has been advised by the doctors. “The situation continues to be closely monitored through regular surveillance, and necessary public health measures are being undertaken,” the scientist said.Delhi ready to fight surge, says govtUnion Health Minister JP Nadda on Friday reviewed the situation in the Capital and the preparedness of healthcare facilities at a key meeting. Nadda emphasised the need for public awareness of preventive measures such as respiratory hygiene and hand hygiene.Story continues below this adThe meeting was also attended by Delhi Health Minister Dr Pankaj Kumar Singh, who reviewed surveillance data and trends in influenza-like illnesses and severe acute respiratory illnesses — cases where patients with flu-like symptoms require hospitalisation.“We are prepared for any situation. There is no shortage of medicine, doctors, beds,” Singh told reporters on Saturday, “Everyone will receive timely and appropriate treatment.”What experts sayIn response to the ICMR findings, Dr S Chatterjee, Internal Medicine Specialist, Apollo Hospital, told The Indian Express, “That’s good news for us. It’s good to know that the mutation has not happened.”He added, “Pollution and environmental factors, among others, could have caused the rise. The air quality around Delhi has worsened over the years, the monsoon has been sporadic, weather has been extreme, dust pollution is also a big issue. Moreover, the defence mechanism of our body has also been weakened. In India, there are multiple factors that weaken our immune systems.”Story continues below this adHe added that although the government has taken preparedness measures, containing the spread was as much an individual responsibility. “It should then be the individual’s responsibility also to control the rise and spread of the disease,” he said. “Wear masks when you go out, wash your hands, avoid crowded spaces if you’re symptomatic, and stay hydrated to help your body fight the infection.”On the other hand, Dr Rommel Tickoo said, “The clarification from ICMR is reassuring. An increase in H1N1 cases does not, by itself, mean that a new or more dangerous strain has emerged. H1N1 is now part of the seasonal influenza spectrum, and most healthy individuals recover with appropriate rest and supportive care. The focus should be on vigilance rather than panic, especially prompt medical attention for high-risk groups such as the elderly, young children, pregnant women and those with chronic illnesses or weakened immunity.”WHO recommendationsEach year, the World Health Organisation comes up with recommendations for the influenza strains that should be included in the annual flu vaccines for the Northern and the Southern hemisphere. The recommendation usually includes two Influenza A strains — one of which is the A/Missouri/11/2025 this year pdm09-like virus this year — and one influenza B strain. These strains are determined using the data on circulation of the flu strains that are reported by its global network of laboratories.“Globally, influenza A virus detections greatly outnumbered those of influenza B, although there were variations in the predominant type and subtype across transmission zones. A(H1N1)pdm09 viruses predominated throughout the reporting period in Eastern Asia and North America, and earlier in the reporting period in South-East Asia; Western Africa; Central America and Caribbean, Temperate and Tropical South America; and Oceania Melanesia and Polynesia,” the previous recommendation from the WHO said.Story continues below this adWhy does the strain matter? Infections are likely to be more severe when a new strain starts circulating and may affect even the vaccinated if it is not a part of the annual flu shot.And, what should you do? Flu is an annual occurrence, with India usually experiencing two peaks each year, one in the colder months between January and March and the second after the monsoons. Flu generally causes severe disease in children below the age of 5 years, the old over the age of 60 years, and pregnant women. Those at risk of severe disease may consider taking the annual flu shot.However, the infection is usually self-limiting and gets better in three to seven days. People who have the flu do not need to take any medication other than paracetamol to lower the body temperature if necessary, according to experts. They should take a lot of fluids to prevent dehydration. And, they should go to a doctor if they have shortness of breath, feel any pain in chest, have blue lips or nails, or the symptoms refuse to improve after a few days.