January 22, 2026

H3N2 Infections: Be Alert But No Need To Panic

By Linus Garg
First publised on 2023-03-11 05:48:00

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Linus tackles things head-on. He takes sides in his analysis and it fits excellently with our editorial policy. No 'maybe's' and 'allegedly' for him, only things in black and white.

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Although just two persons have died after being infgected by the H3N2 virus in India, the Centre has rightly asked all states to be on alert. This is because H3N2 is a subtype of Influenza A virus which causes more hospitalizations than other influenza subtypes. If not controlled, it can also be fatal. Hence, despite influenza viruses are considered to be self-limiting and benign, H3N2 causes problems and needs to be monitored closely. The symptoms of H3N2 are similar to that of any other flu. Patients will suffer from cough, fever, body ache and headache, sore throat, a runny or stuffy nose and extreme fatigue. They might suffer nausea, vomiting and diarrhoea in rare cases. The infection lasts for five to seven days and fever may subside after three days but coughing might persist for nearly three weeks.

In India this year, persons suffering from infections "are reporting prolonged cough, persistent fever and other complications", said Dr G C Khilnani, chairman of PSRI Institute of Pulmonary, Critical Care and Sleep Medicine (reported in The Times of India) and this is leading to increased hospitalization. The health ministry has said that ICMR network of laboratories are closely monitoring the human influenza virus subtypes and it has been seen that nearly 79% of all cases of people infected have been found to be H3N2. This has led the Centre to put the states on alert. Apart from H3N2, Influenza B Victoria was found in 14% persons and H1N1 (also known as swine flu) was found in 7%.

Health minister Mansukh Mandaviya held a review meeting as the cases were rising. The advisory to the states asking them to be alert and monitor the situation closely was issued after the meeting. Although there is no reason to panic, people suffering from Severe Acute Respiratory Illness (SARI) or Influenza Like Illness (ILI) need to be monitored as they are most susceptible. Since the virus is self-limiting, it is hoped that with the onset of summer, cases will decline. But in the interim, states will have to be on guard so that H3N2 does not spread. Hospitals all over the country must also be ready any eventuality.