Clinical Management, Vaccination Protecting People From Seasonal Influenza: Expert

New Delhi: India registered 14 deaths due to Seasonal Influenza A (H1N1) so far in 2025 against 347 last year, with experts saying this was made possible with proper follow-up of clinical management and vaccination.

“Proper clinical management and on-time vaccination could be the major causes for such an improved situation. Proper vaccination and doctors’ guidance also help the patients in fighting such seasonal influenza,” said Dr Ashok Grover, a chest specialist from Delhi’s Max hospital.

People, especially the elderly, those suffering from asthma and chronic illnesses, get influenza vaccine shots every year, said Dr Grover.

According to health ministry data in possession of ETV Bharat, in 2024, Maharashtra, Kerala and Gujarat registered 71, 61 and 55 deaths respectively due to H1N1. This year, the number of fatalities is 0, 8 and 3, respectively.

As many as 3,320 cases of seasonal influenza have been reported across the country in 2025, as against 20,414 cases of seasonal influenza last year. "In several cases, patients don’t require testing, and in some cases, doctors may not advise testing if the symptoms are minor,” said Dr Grover.

Asked about the lower number of seasonal influenza cases registered this year, Dr Grover said, "It depends on the number of clinical and documented cases." In clinical cases, the patients are not advised to go for any testing by the doctors, whereas in documented cases, the patients are advised for all necessary testing, said Dr Grover.

According to the clinical management protocol of the health ministry, influenza (also known as flu) is a contagious respiratory illness caused by flu viruses.

"People who have influenza-like illness (ILI) may experience muscle or body aches, headaches, fatigue, vomiting and diarrhoea (more common in children than adults), running or stuffy nose," the clinical protocol said.

According to the health ministry protocol, all individuals seeking consultations for flu-like symptoms should be screened at healthcare facilities, both Government and private or examined by a doctor and categorised into A, B and C to prevent and contain outbreaks of influenza.

Category- A (uncomplicated/mild)

Symptomatology: Patients with mild fever and cough/ sore throat with or without body aches, headache, diarrhoea and vomiting will be categorised as Category-A.

Diagnostic test: Testing of such patients for influenza is not required

Category-B (uncomplicated but severe symptoms / high-risk groups)

Symptomatology: In addition to all the signs and symptoms mentioned under Category-A, if the patient has high-grade fever (≥102 F) and severe sore throat.

Diagnostic test: Testing of the patient for influenza is not required.

Category-C (Complicated)

Symptomatology: In addition to the signs and symptoms of Category-A and Category-B, if the patient has one or more symptoms like breathlessness, hemoptysis, altered mental status etc.

Diagnostic test: These patients should be tested for influenza; start empirical antiviral therapy (oseltamivir) while results are pending.

According to another Delhi-based physician and pulmonologist, Dr Ashish Jain, "Timely consultation of doctors and proper awareness could be the factors for such an improving situation."

He, however, said the number of cases depends on the registration of a particular type of influenza.

“Maybe this time, the number of H1N1 cases is low, and the number of other influenza cases is high,” said Dr Jain.

According to the World Health Organisation (WHO), there are four types of influenza viruses, including A, B, C and D. “Influenza A and B viruses circulate and cause seasonal epidemics of disease,” WHO said.

Influenza A viruses are further classified into subtypes according to the combinations of the proteins on the surface of the virus.

“Currently circulating in humans are subtypes A(H1N1) and A(H3N2) influenza viruses. The A(H1N1) is also written as A(H1N1)pdm09 as it caused the pandemic in 2009 and replaced the previous A(H1N1) virus, which had circulated before 2009. Only influenza type A viruses are known to have caused pandemics,” the WHO said.

According to the global health watchdog, influenza B viruses are not classified into subtypes but can be broken down into lineages.

“Influenza type B viruses belong to either B/Yamagata or B/Victoria lineage. Influenza C virus is detected less frequently and usually causes mild infections, thus it does not present public health importance. Influenza D viruses primarily affect cattle and are not known to infect or cause illness in people,” the WHO said.

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