No need for masks as H1N1 drives seasonal flu surge, says ICMR chief

New Delhi: India is witnessing a seasonal rise in respiratory infections driven primarily by Influenza A subtype H1N1, along with minor circulation of H3N2, Influenza B (Victoria lineage), and mild SARS-CoV-2 cases, Dr Rajiv Bahl, director general of the Indian Council of Medical Research (ICMR), said on Tuesday.

“There should not be any cause of panic that we can see, any cause of concern. It is a large number of cases with the same H1N1 strain, which is the seasonal influenza,” Dr Bahl said during a media briefing at ICMR headquarters in New Delhi.

Dr Bahl said H1N1 accounts for nearly 98% of circulating Influenza A cases, with H3N2 making up the rest. He confirmed that 98-99% of all cases remain mild, self-limiting, and manageable at home with rest, hydration and basic care.

Prevention & care

Instead of masks, Dr Bahl advised standard hand hygiene, respiratory etiquette, and maintaining a distance of one to two meters from symptomatic individuals to avoid heavy respiratory droplets. He also noted that high-risk groups—including adults aged 65 and above, pregnant women, and immunocompromised individuals—can opt for the Northern Hemisphere flu vaccine in consultation with their physicians.

“We are not asking people to wear masks because respiratory droplet infections travel at most one to two meters. As far as flu vaccines are concerned, we have done a cost-effectiveness analysis in India and there is no decision that it should be done universally under the national immunization programme. However, the Northern Hemisphere vaccine formulation is available, and high-risk groups can opt for it in consultation with their doctors,” he added.

Dr. Bahl, who is also secretary of the department of health research (DHR), said the circulating influenza strains remain sensitive to standard antivirals like oseltamivir (Tamiflu), though unprescribed use of antivirals and antibiotics is strictly discouraged as antibiotics are ineffective against viral illnesses, and antivirals should only be taken when prescribed for severe cases.

So far this year, Delhi has reported over 2,600 influenza cases characterized by sudden onset of high fever and sore throat, with the H1N1 strain accounting for nearly 70% to 75% of total infections. Other states significantly affected by influenza include Karnataka, Maharashtra, and Kerala.

Mint previously reported that the sharp uptick had prompted Union Health Minister J.P. Nadda to chair a high-level review meeting on 21 August to evaluate the country’s epidemiological situation, national surveillance mechanisms, and public health preparedness.

Real-time tracking

Addressing concerns around the strain’s evolution, Dr Bahl explained that H1N1 is no longer swine flu; it now spreads strictly from human to human and has effectively become a seasonal flu that resurfaces every year. “Flu viruses have a very classical way of behaving; they keep on having small mutations every year. That mutation helps them to keep on infecting people even if they had the flu last year,” he said.

To closely monitor these annual mutations, real-time syndromic surveillance is actively tracking trends across 73 sentinel hospitals and 167 virus research and diagnostic laboratories (VRDLs) nationwide.

Dr Bahl explained that the apex health research body tracks transmission through structured sentinel sites. “There are 73 labs and 73 hospitals all across India where our sentinel surveillance of ICMR is also there… Every week, 25 samples are tested from SARI (Severe Acute Respiratory Infection) and other respiratory infections… 25 times 73 tests are done for all viruses,” he said.

He added that 167 VRDLs established across government medical colleges are actively processing samples against a 10-virus syndromic panel that tests for Influenza A, Influenza B, SARS-CoV-2, Respiratory Syncytial Virus (RSV), Adenovirus and Parainfluenza.