No mismatch between circulating flu strains and vaccine strains

Influenza instances peak throughout monsoon season with a secondary peak throughout winter
| Photograph Credit score: CDC/Douglas Jordan

On March 7 and March 8, a number of newspapers reported a surge in influenza (flu) instances within the Delhi-NCR area, with some mentioning the “spike” as over 54%. The supply of this information was an area survey (LocalCircle) of over 13,000 individuals within the Delhi-NCR area. Whereas the estimate was not primarily based on medical testing however on frequent viral fever signs, and the press launch had solely talked about “viral sicknesses (Covid/flu/viral fever)”, newspaper reviews attributed the “spike in instances” to influenza.

In line with NCDC’s Built-in Illness Surveillance Programme (IDSP) information posted on February 27, 2025, there have been 516 influenza instances and 6 deaths in January this 12 months. The variety of flu instances throughout India for all of 2024 was 20,414 with 347 deaths. It’s tough to say if the instances reported in January this 12 months are greater than the identical month final 12 months as IDSP doesn’t present segregated month-to-month information. In contrast with IDSP, the U.S. CDC gives a weekly influenza surveillance report.

Whereas influenza an infection does happen year-round in India, it peaks throughout monsoon season with a secondary peak throughout winter.  As per a Might 2023 Viewpoint within the Indian Journal of Medical Analysis, influenza causes “substantial illness and deaths” yearly in India. Acute respiratory an infection (ARI) surveillance between 2016 and 2018 by six centres unfold throughout India discovered 15.4% instances had been influenza, whereas 12.7% of extreme acute respiratory an infection (SARI) instances had been influenza. Estimating the variety of flu deaths is a problem as “routine testing for influenza just isn’t accomplished in medical settings and influenza is never licensed as a reason behind loss of life”.

By modelling ‘extra’ deaths utilizing loss of life information from the Pattern Registration System and virological information from the influenza surveillance community of 10 labs throughout eight States from 2010-2013, a June 2020 paper estimated a imply of 1,27,092 influenza-associated respiratory and circulatory deaths per 12 months in India. Estimated flu-associated deaths was excessive amongst adults over 65 years and youngsters below 5 years. But, in keeping with the Might 2018 pointers for influenza vaccination issued by the Well being Ministry, influenza vaccine is simply thought-about “fascinating” for individuals older than 65 years and youngsters under 5 years.

WHO recommends the influenza strains for use within the vaccine for the approaching flu seasons months prematurely primarily based on the strains which might be presently circulating. On February 28, 2025, WHO introduced the suggestions for influenza vaccine composition for the 2025-2026 northern hemisphere influenza season. The suggestions made months earlier than the subsequent flu season provides the producers enough time to make vaccines. Although there are just a few methods to make flu vaccines, together with cell-based and recombinant vaccines, the commonest methodology is to make use of hen eggs to develop the virus strains. Egg-based vaccine manufacturing takes months to complete. Serum Institute’s influenza vaccine is egg-based, whereas Sanofi makes each egg-based and recombinant vaccines.

Whereas generally the strains utilized in influenza vaccines match with the strains that flow into within the following season, at occasions the match just isn’t excellent resulting in diminished vaccine effectiveness. “When vaccines are launched, they symbolize strains recognized from the earlier 12 months’s circulating viruses. Whereas seasonal mismatches between WHO-declared strains and precise circulating strains can happen, no such mismatch has been reported this time. Presently, the circulating pressure in north India is predicted to align with the WHO-identified strains for the area,” Dr Rajeev Dhere, Senior Scientific Advisor, Serum Institute tells The Hindu.

As of February 15, 2025, for the 2024-25 season, an estimated 57 million doses of flu vaccine had been administered to adults within the U.S, and as of March 1, 2025, practically 47% of youngsters obtained a flu vaccine. Influenza vaccine uptake in India has been traditionally low. It has not elevated considerably regardless of a number of the worst flu outbreaks in recent times — 2015 recorded probably the most variety of instances (42,592) and a couple of,990 deaths in India. Although not on the identical scale, there have been massive flu outbreaks since 2015 — in 2017 there have been 38,811 instances and a couple of,270 deaths, 28,798 instances and 1,218 deaths in 2019, and 20,414 instances and 347 deaths in 2024. Influenza vaccine just isn’t a part of India’s common immunisation programme.

As per the Well being Ministry pointers, healthcare employees “must be vaccinated”. The vaccine is “really helpful” for pregnant ladies, and youngsters and adults with continual sicknesses, whereas it’s “fascinating” for adults older than 65 years and youngsters below 5 years regardless of the excessive mortality within the two excessive age teams. A 2022 examine discovered that only one.5% of adults aged 45 years or older had been ever vaccinated for influenza.

“Influenza vaccine uptake in India stays low (lower than 5%). Whereas the market has proven vital year-on-year progress, total protection stays insufficient resulting from low public consciousness and the absence of widespread programmes. We have now noticed an elevated uptake of flu vaccines in India with the market rising by 21% in 2025 vs 2024,” says a Sanofi spokesperson. Serum manufactures 3,00,000-4,00,000 doses and may scale as much as over one million relying on the demand, Dr. Dhere says.