Written by Ankita UpadhyaySeptember 19, 2025 07:50 AM IST 6 min readThe H3N2 virus is contagious, airborne and spreads fast in crowded places, especially a confined and unventilated office environment. (File/Representational Photo)10 am: There’s an unusual crowd at the internal medicine wing of Apollo Hospital, Delhi. Almost all of them are masked up, restless, have malaise and headaches and are retching and coughing alternately. Some have high fever that even the familiar paracetamol has not been able to tame. “There is a surge of respiratory viral infections caused by H3N2, a strain of the influenza virus, which this year has become more persistent, with cough and fatigue lasting two weeks after recovery. The symptoms are intense,” says senior consultant, Dr Suranjit Chatterjee.One of the patients is a 38-year-old software engineer, who has been working remotely but now needs to travel to his office in Noida for meetings. He is currently battling a high-grade fever and requires medication to recover in time so that he can keep to the office mandate of the not-to-be missed Friday strategy meeting. “I began experiencing symptoms two days ago, including a persistent high fever, severe cough, cold, and a sore throat, all of which are indicative of a respiratory viral infection. Concerned about the possibility of COVID-19 or influenza and fearing I might be contagious, I came to see the doctor,” he says.Another case involves a 50-year-old auto spare parts manufacturer from Faridabad and his 15-year-old son. “I had high temperature for a day and at night my son developed high fever . This virus is contagious. Which is why we chose to isolate ourselves from other members of our family,” says the father. At least some learnings of Covid have made people conscious about how to manage viral infections. “Testing has increased, lab services are more accessible and that could be one of the reasons that more cases are being identified early enough,” says Dr ChatterjeweMapping the spreadThe H3N2 virus is contagious, airborne and spreads fast in crowded places, especially a confined and unventilated office environment. “This time, patients are presenting themselves with a very high fever of 104°F with severe body aches and headaches. The symptoms are more felt and pronounced. That’s what’s troubling people. Even the usual paracetamol isn’t always working well,” he says.Dr Chatterjee has not observed a new strain but insists there may have been slight mutations that are typical of any seasonal virus.According to Dr Lalit Dar, professor of microbiology at the All-India Institute of Medical Sciences (AIIMS), Delhi, H3N2 is a specific strain or subtype of the Influenza A virus, not a separate virus. “Influenza A is a broad category of viruses that includes H3N2, as well as other subtypes like H1N1. Therefore, all H3N2 viruses are a type of Influenza A, but not all Influenza A viruses are H3N2. There is also influenza B (which is characterised by gastrointestinal symptoms and diarrhoea). They appear every season but some strains tend to predominate each year. They appear after every monsoon season and have a second peak between January and March in parts of north India,” he says.Are more young people getting affected?The symptoms are not only intense but the flu is largely being reported by young and middle-aged adults, most of whom are professionals unable to afford time-offs. “Most of my patients are under 40. Their workplaces have a closed environment and they’re under pressure to show up despite being unwell. Many just want medication strong enough to get them through the day,” he says. Besides work stress, a poor lifestyle means the body is more prone to inflammation, which damages healthy tissue and reduces the body’s immunity. “They don’t sleep enough, work long hours, eat poorly and that’s especially true for the younger crowd. Add crowded metros, shared taxis, poorly ventilated offices — it’s a perfect storm for airborne viruses like this,” Dr Chatterjee adds.Story continues below this adWhat about treatment protocol?However, there is a treatment dilemma that goes beyond symptom control. With dengue also circulating during the monsoon season, physicians are treading carefully. “You can’t immediately give medications like mefenamic acid or Nimesulide unless you’re sure the fever is not because of dengue. Nimesulide is not recommended for treating dengue fever because it is a non-steroidal anti-inflammatory drug (NSAID) and can increase the risk of serious complications, such as gastrointestinal bleeding and kidney damage, similar to other NSAIDs like ibuprofen and aspirin. That makes symptom management a bit tricky in the early days without a test,” says Dr Chatterjee.Once confirmed, doctors are advising their patients to get ample rest, for at least 10 days, stay well-hydrated and use pain relievers and fever reducers to help manage their symptoms. They are also insisting on maintaining physical distance from other family members to prevent further transmission.“Earlier, for a runny nose or sore throat, people wouldn’t even visit a doctor, let alone get tested. But since COVID, even mild respiratory symptoms push people to get a lab test. That’s why they’re coming back positive for H3N2 more frequently,” says Dr ChatterjeeWho’s at risk?Despite the surge in cases, most people are recovering at home. Hospital admissions remain limited to the most vulnerable who are living with comorbidities like diabetes, kidney or liver disease, heart conditions and those who are immunocompromised.Story continues below this ad“We’re seeing some admissions among transplant patients and those with uncontrolled diabetes or organ failure. These are mostly elderly people. Still, nothing too alarming — but enough to keep us cautious,” says Dr Chatterjee.Dr Dar says people with comorbidities need to remain alert. “Like any other respiratory virus, just like you saw with COVID, H3N2 could result in a severe manifestation of the infection. Severe disease would be less than one per cent most of the time. This is the usual pattern,” he adds.© The Indian Express Pvt Ltd