No Mismatch Between Circulating Influenza Strains and Vaccine Strains

No Mismatch Between Circulating Influenza Strains and Vaccine Strains

Sub :Sci

Sec :Health

Why in News

• The World Health Organization (WHO) has announced the influenza vaccine composition for the 2025-2026 northern hemisphere flu season. Concerns were raised after reports of a surge in influenza cases in the Delhi-NCR region, but there is no mismatch between circulating flu strains and vaccine strains this time.

Surge in Influenza Cases in India:

• NCDC’s Integrated Disease Surveillance Programme (IDSP) reported 516 influenza cases and six deaths in January 2025.
• A 2023 study in the Indian Journal of Medical Research highlighted that influenza causes substantial disease burden and deaths annually.
• High mortality is observed among children under five and adults over 65 years.

About Influenza:

• Influenza is a viral disease. It is caused by Orthomyxovirus (influenza virus) pathogen.
• It is a contagious disease, which means it can be spread easily from person to person.
• Viruses that cause influenza spread from person to person mainly by droplets of respiratory fluids sent through the air when someone infected with the virus coughs or sneezes.
• Influenza A viruses infect humans and many different animals. Influenza type A viruses are of most significance to public health due to their potential to cause an influenza pandemic.
• Influenza type A viruses are classified into subtypes according to the combinations of different virus surface proteins hemagglutinin (HA) and neuraminidase (NA).
• Fever, respiratory symptoms like cough and runny nose, as well as other symptoms including body aches, nausea, vomiting, or diarrhoea, are some of the prominent symptoms of the virus.
• WHO recommends influenza strains months in advance based on currently circulating strains.
• Vaccine development methods include egg-based, cell-based, and recombinant vaccines.
• Influenza vaccines are formulated based on the previous year’s circulating strains.
• Influenza vaccination is not part of India’s Universal Immunisation Programme.
• Ministry of Health guidelines (2018) classify flu vaccines as:
  • Mandatory for healthcare workers.
  • Recommended for pregnant women, children, and adults with chronic illnesses.
  • Desirable for adults over 65 years and children under five, despite their high mortality risk.
• A 2022 study found that only 1.5% of Indian adults aged 45 and above had ever received an influenza vaccine.

Recent Trends:

• Influenza vaccine coverage remains below 5% in India.
• Despite year-on-year market growth, public awareness remains low.
• In 2025, flu vaccine demand increased by 21% compared to 2024, according to Sanofi.
• Serum Institute produces 3-4 lakh doses annually and can scale up production based on demand.