H1N1 Makes Up 98% Of Influenza A Cases In India: ICMR Chief, Pg14

Key Highlights:

• The H1N1 strain currently accounts for approximately 98% of Influenza A cases detected in India.
• H3N2 constitutes only 2% to 3% of the reported Influenza A cases.
• Indian Council of Medical Research (ICMR) Director-General Rajiv Bahl stated there is no cause for panic, as the circulating virus is the familiar H1N1 pdm09 strain from the 2009 pandemic.
• The ICMR confirmed that the infections are largely mild and self-limiting, with no urgent need for general population vaccination.
• India's influenza surveillance is conducted through a network of 73 sentinel hospitals, tracking various respiratory viruses.

Detailed Insights:

• The H1N1 pdm09 strain has become a seasonal influenza virus since its emergence in 2009.
• Minor genetic changes in influenza viruses occur naturally each season and do not indicate a new or more dangerous strain.
• Vaccination for seasonal flu is primarily recommended for individuals aged above 65 and those who are immunocompromised, after consulting their doctors.
• The ICMR network of 73 Virus Research and Diagnostic Laboratories (VRDLs) monitors influenza trends across the country.
• This surveillance system also tracks other viruses like SARS-CoV-2, human metapneumovirus, adenovirus, and parainfluenza viruses.
• The current H1N1 lineage, identified as A/Missouri/11/2025 (H1N1) pdm09-like, has been circulating in India since 2025.

Key Concepts Involved:

• Influenza A: A type of influenza virus that can cause seasonal epidemics and is known to cause flu pandemics.
• H1N1: A subtype of Influenza A virus, responsible for the 2009 pandemic and now a seasonal flu strain.
• H3N2: Another subtype of Influenza A virus, characterized by specific surface proteins (Hemagglutinin H3 and Neuraminidase N2).
• Indian Council of Medical Research (ICMR): India's apex body for the formulation, coordination, and promotion of biomedical research.