H3N2 Virus: Everything you need to know about

According to ICMR, the recent uptick in cases of intense cough lasting for over a week coupled with fever, in several parts of India, can be linked to the influenza A subtype H3N2 virus.

Amid the looming concerns of the H3N2 virus in the country, several states are taking steps to curb the virus. Seasonal influenza is a respiratory tract infection caused by four distinct types of viruses (A, B, C, and D) belonging to the Orthomyxoviridae family. H3N2 has been the dominant subtype followed by H1N1.

It is to be further noted that both these subtypes belong to Influenza ‘A’ type.

Meanwhile, the Union Ministry of Health on Friday said that the cases arising from seasonal influenza including H3N2 are expected to decline from March end.

India has recorded deaths of two people, one each in Karnataka and Haryana, due to the Influenza A subtype H3N2 virus. It added that around 90 cases of this virus have been reported across the country.

What is the H3N2 virus?

Influenza viruses, which cause the infectious disease known as flu, are of four different types: A, B, C, and D. Influenza A is further classified into different subtypes and one of them is the H3N2. According to the United States Centres for Disease Control and Prevention (CDC), H3N2 caused the 1968 flu pandemic that led to the death of around one million people globally and about 100,000 in the US.

A 2020 study, published in the journal Nature Communications, found that the strains of the virus have dramatically evolved in the past five decades as people born in the late 1960s and 1970s got infected by it as children.

What are the symptoms of H3N2?

Its symptoms are similar to that of any other flu. They include cough, fever, body ache and headache, sore throat, a runny or stuffy nose, and extreme fatigue. Nausea, vomiting, and diarrhoea have been seen in very few cases.

According to the Indian Medical Association (IMA), an infection caused by H3N2 generally lasts for five to seven days and the fever starts going away after three days. However, the coughing can persist for up to three weeks.

Which age group is more vulnerable?

As per the IMA, this virus usually preys on individuals below the age of 15 years or above 50 years of age. Children and those with co-morbidities like asthma, diabetes, heart disease, weakened immune systems, and neurological or neurodevelopmental conditions are at a higher risk.

Let’s see what the respective states are doing to overcome the situation

Delhi

Lok Nayak Jai Prakash Narayan Hospital in the national capital has come with 20 bedded isolation wards for infected patients with all the facilities like oxygen facilities, ventilators, and a team of 15 doctors who are doing round-the-clock duty, the Medical Director, told ANI.

Maharashtra

Maharashtra health minister Tanaji Sawant noted that 352 patients of the H3N2 virus have been reported so far in the state and further asserted that there is no need to panic. As of March 13, 2023, Maharashtra has tested 256,424 patients for influenza. Union Health Secretary Rajesh Bhushan emphasized the significance of increasing community awareness and encouraging the timely reporting of symptoms and highlighted the importance of limiting contact with individuals exhibiting signs of respiratory illness.

Assam

The Health Department official of Assam confirmed the first case of the H3N2 virus. The Department is actively monitoring the developing situation of Seasonal Influenza throughout the state using the Integrated Disease Surveillance Programme (IDSP) network in real time.

Karnataka

Karnataka reported its first death by the H3N2 influenza virus last week.

Meanwhile, the state health minister Dr. K Sudhakar chaired a meeting with the officials given the rise in cases, and ordered them to remain patient. The

department is monitoring the variants by screening 25 cases of Sari and ILI per week at Victoria and Vani Vilasa Hospitals, in line with the target of 25 tests per week. From January to March, 20 cases of H1N1 were identified along with 26 cases of H3N2, 10 cases of Influenza B, and 69 cases of Adeno, according to the statement.

Tamil Nadu

To curb the rising case of H3N2 influenza, Tamil Nadu health minister Ma Subramanian has set up 1,000 fever camps all over the state of which 200 are in Chennai.

“PTPCR tests are done and the number of tests has been increased. There were only 2 cases last month but now it’s 20 to 25 cases in Tamil Nadu and we are preparing to curtail it,” assured the Health Minister. As per the administration, the fever camps are functional even on Saturday and Sunday.

Odisha

The Health Secretary of Odisha has instructed all district administrations to increase influenza-like illness (ILI) and severe acute respiratory infections (SARI) surveillance at both health facility and community levels due to the recent increase in H3N2 virus cases in the state, according to the Department of Health.

The Health Department stated that 30 DPHLs are closely monitoring the trend of ILI and SARI cases by conducting regular sample testing in 23 RTPCR labs and DPHLs. H1N1 testing is also being conducted regularly by the 30 DPHLs. They are well-equipped with the necessary infrastructure and laboratory logistics to conduct tests in case of a surge in the future.

Puducherry

With the outbreak of the H3N2 virus, all schools in Puducherry will remain shut from 16 March (Thursday) to 26 March (Sunday).

As of 11 March, Puducherry reported 79 cases of influenza, belonging to the viral H3N2 subtype so far. But no death related to H3N2 has been reported in the union territory till now.

Additionally, since January 1, as per testing of respiratory samples being undertaken by various viral research and diagnostic labs (VRDLs), almost 25.4% of the samples have tested positive for adenoviruses