H3N2 in Puducherry: All schools to remain closed for 10 days as Centre raises concern

The Union Health Secretary Rajesh Bhushan, in a letter to states and UTs, stated that despite a low number of new cases and significant advances made in terms of COVID-19 vaccination coverage, there is a need to remain vigilant and focus on the five-fold strategy of test, track, treat, vaccination, and adherence to Covid-appropriate behaviour.

Bhushan also mentioned that under the Integrated Disease Surveillance Programme (IDSP), an increasing trend of ILI/SARI is being observed across the country.

Furthermore, according to integrated sentinel-based surveillance of ILI and SARI, an upswing of Influenza A is observed since the latter half of December last.

"Of particular concern is the preponderance of Influenza A (H3N2) being detected in the samples being analysed in various labs. It should also be kept in mind that young children, old age people and people suffering from co-morbidities are particularly at risk and vulnerable to H1N1, H3N2, adenoviruses, etc," he said.

Bhushan urged states and UTs to raise community awareness regarding adherence to respiratory and hand hygiene and promoting early reporting of symptoms and limiting contact with those suffering from respiratory illnesses.

The letter also stated that all states and UTs must implement 'Operational Guidelines for Revised Surveillance Strategy in Context of COVID-19,' which provides for integrated surveillance of respiratory pathogens presenting as cases of ILI/SARI.

Puducherry, a union territory in India, has reported 79 cases of influenza belonging to the H3N2 subtype, according to a health official on Saturday.

G Sriramulu, Director of Medical Services in Puducherry, said that the cases were reported until March 4, but there have been no deaths due to the virus in the union territory.

Sriramulu assured the public not to panic, as the health department has made arrangements at hospitals and primary health centres to monitor the rising cases.

Special booths have been opened in outpatient departments for those showing symptoms of the influenza virus. The official urged people to follow COVID-19 pandemic guidelines, including washing hands, wearing face masks, and avoiding crowded places.

However, an ICMR report has predicted that H3N2 cases will decrease by the end of March.

H3N2 is a non-human influenza virus that typically circulates in pigs and has infected humans. Its symptoms are similar to those of seasonal flu viruses, including fever and respiratory symptoms, body aches, nausea, vomiting or diarrhoea.

Experts are calling for increased monitoring and precautionary measures to ward off the H3N2 influenza virus, which has claimed two lives in India. An 82-year-old diabetic patient with hypertension died in Karnataka, while a 56-year-old lung cancer patient passed away in Haryana due to the seasonal influenza subtype. From January 2 to March 5, there have been 451 confirmed cases of H3N2 in India, according to data shared by the Ministry of Health and Family Welfare.

While there is no need to panic yet, experts recommend taking precautions similar to those taken during the Covid pandemic. Prolonged use of masks during the pandemic may have decreased immunity against regular respiratory viruses.

"Due to at least two years of elaborate, expansive use of masks, we might have lost part of our immunity against the versions of these other respiratory viruses that are now getting transmitted," said virologist Upasana Ray, an alumni member of the Indian National Young Academy of Science (INYAS) and member of Global Young Academy (GYA).

H3N2 is a non-human influenza virus that normally circulates in pigs and can infect humans, according to the US Centre for Disease Control and Prevention (CDC). Symptoms are similar to those of seasonal flu viruses and can include fever, respiratory symptoms such as cough and runny nose, body ache, nausea, vomiting or diarrhea.

Experts note that while H3N2 outbreaks can cause death and are more severe than regular flu, there is general immunity to flu and vaccines exist. Pulmonologist Anurag Agrawal said he doesn’t expect to see a massive wave of H3N2 cases. "Admission to hospital has not been very common and only about 5 percent cases have been reported to be hospitalized," added Tarun Sahani, senior consultant, internal medicine, Apollo Hospitals.

India is witnessing a huge spike in H3N2 cases since the start of 2023.

"The incidence is two to three times higher than usually seen at this time of the year. This virus is known to be a subtype of Influenza A virus which is common at this time of the year," Sahani told PTI.

According to the latest data available on IDSP-IHIP (Integrated Health Information Platform), a total of 3,038 laboratory-confirmed cases of various subtypes of Influenza including H3N2 have been reported till March 9 by the states.

The Union Health Ministry is keeping a close watch on the seasonal influenza situation in various states/UTs through the Integrated Disease Surveillance Programme (IDSP) network on a real-time basis.

Experts urge disease monitoring as an urgent need to address the situation. "In coming times we will have better combined respiratory virus surveillance," said Agrawal, the former director of the CSIR-Institute of Genomics and Integrative Biology. While the Covid pandemic seems to be ending, the spate of respiratory illnesses continues among adults with a significant number being infected with influenza viruses such as H3N2, adenovirus, and H1N1.