H1N1 Dominates 98 Per Cent of Influenza A Cases in India: ICMR Director-General Rajiv Bahl

New Delhi: Indian Council of Medical Research (ICMR) Director-General Rajiv Bahl on Tuesday said that the H1N1 strain of Influenza A has emerged as the overwhelmingly dominant respiratory pathogen circulating across India, accounting for nearly 98 per cent of tested Influenza A cases.

Addressing a press conference, Bahl highlighted that India has established a multi-tiered, real-time disease surveillance network across the country to track viral outbreaks. The surveillance infrastructure links state-level data through the Integrated Health Information Platform (IHIP) and National Centre for Disease Control (NCDC), layered with direct hospital-based sampling by ICMR to instantly flag rising respiratory infections, such as H1N1 influenza and trigger immediate outbreak responses.

"The first thing is: how do we know which viruses are circulating? India, particularly post-COVID, has really enhanced our ability to detect, at any point in time, in real time, what is happening in India. We conduct surveillance at multiple levels. First, through IHIP and NCDC surveillance, where reporting comes from all states on whatever is happening and what infections are occurring. So, we get to know all of that. The reports coming from their labs are also known to us. Apart from that, for every syndrome, like this respiratory virus, we have established sentinel surveillance through ICMR across 73 labs or 73 hospitals all across India. This is one layer on top of the NCDC layer," he said.

Bahl also revealed that real-time nationwide surveillance shows an overwhelming surge in H1N1 infections relative to other respiratory strains, while COVID-19 cases continue to follow a steady downward trajectory. "Currently, respiratory surveillance shows that there is a lot of circulating H1N1, which is Influenza A. There is Influenza A and Influenza B; both occur in humans. In Influenza A, what we are finding most commonly is H1N1, which makes up about 97 per cent to 98 per cent, while H3N2 is only around 2 per cent to 3 per cent. In addition, we are also finding some Influenza B circulating, which is of the Victoria lineage. There are two lineages, but nowadays only one circulates, though it is not predominant; H1N1 remains predominant. Thirdly, for SARS-CoV-2 (COVID-19), a few cases were slightly higher earlier, but now they are on a declining trend," he said.

Seasonal influenza, including H1N1, is "mostly self-limiting". Common symptoms include fever, cough, headache and body aches, and most people recover with appropriate care and adequate rest, the ICMR added in their statement.