Delhi has recorded over 1,777 H1N1 cases this year. ICMR said the circulating strain matches Northern Hemisphere vaccines. Two options: intranasal spray or injected shot.
Alpha Score of 66 reflects moderate overall profile with strong momentum, moderate value, moderate quality. Based on 3 of 4 signals – score is capped at 90 until remaining data ingests.
The Indian Council of Medical Research said Sunday that no new strain of influenza A (H1N1) is circulating in the country, as Delhi reported more than 2,300 influenza-A cases this year, including over 1,777 H1N1 infections through Friday. A single day – Thursday – saw 114 new H1N1 cases, the city's health department said.
The viruses now circulating are similar to the A/Missouri/11/2025 (H1N1) pdm09-like strain, belonging to clade 6B.1A.5a2a and subclade D.3.1.1, an ICMR scientist told PTI. Those strains have been in circulation since 2025. "There is no cause for panic," the scientists said.
H1N1 is mostly self-limiting. Children, the elderly, and people with underlying conditions face higher risks. Common symptoms include fever, cough, headache and body ache. Most people recover with rest and appropriate care, the scientists said. They advised seeing a doctor if symptoms persist or worsen.
The ICMR also confirmed that the circulating strains match the vaccine strains recommended for the Northern Hemisphere. The National Centre for Disease Control has recommended using the Northern Hemisphere vaccine for the 2026-2027 influenza season.
Vaccine options and who should take them
Two main vaccines are available in India. NASOVAC-S4 is a live attenuated quadrivalent intranasal spray for people above 2 years old. A single 0.5 ml dose – 0.25 ml per nostril – is administered. This spray is not recommended for pregnant women or people with certain medical conditions.
VaxiFlu S is a trivalent inactivated injection containing two A strains (H1N1 and H3N2) and one B strain (Victoria). It is given intramuscularly by a trained professional. For children between 6 months and 9 years who have not been vaccinated before, two doses are given at least four weeks apart. Those already vaccinated get a single annual dose. For people above 9 years, adults, and seniors, a single annual dose is recommended, ideally before flu season.
Director General of Health Services Dr Loveneesh G Krishna told ANI last week that vaccination can reduce the severity of H1N1 infection. "The flu vaccine is the best protection against the flu. If you get the flu vaccine, you are 60% less likely to need treatment for the flu," Max Healthcare states on its website.
The Indian Medical Association recommends influenza vaccines for children above 6 months, adults over 50, patients with chronic conditions, pregnant women, and healthcare providers. The inactivated shot is safe for all these groups. The live nasal spray is restricted to people aged 2 to 49 years and is not for pregnant women.
When to vaccinate and what to know
It takes about two weeks after vaccination for antibodies to develop. People remain at risk of catching the flu during that window, which is why getting vaccinated before the season starts matters. Those with a fever should wait until it resolves before getting the shot. A mild respiratory illness without fever does not prevent vaccination.
Consult a doctor before getting an influenza vaccine if you have specific allergies, comorbidities, a history of severe reactions, or an acute moderate-to-severe illness with fever. Vaccination is a preventive measure, not a cure. It helps build immunity so infection is less likely.
The ICMR said the strain match means current vaccines should work. The NCDC has endorsed the Northern Hemisphere vaccine for the coming season.
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