H3N2 Influenza Virus: Is it Pandemic?


Mrs. Emy Jancy Rani J.

Assistant Professor, M. Sc Nursing (Community Health Nursing) Shri Sathya Sai College of Nursing, Ammapettai Village, Kancheepuram District, Pin – 603108.

*Corresponding Author E-mail: demynurse@gmail.com



The H3N2 subtype evolved from H2N2 virus and caused the pandemic in 1968-69 in Hong Kong. A total of 293 patients with influenza like illness were investigated during the course of continuous surveillance on influenza in Pune, India in 2000. The throat/nasal swab specimens collected from these patients were inoculated in MDCK cell culture and influenza types A(H3N2), A(H1N1) and type B strains were isolated. They were identified as similar to the recently prevalent variant strains; A/Sydney/05/97(H3N2), A/New Caledonia/20/99(H1N1) and B/Sichuan/379/99. The latter two were the new variant strains reported for the first time in Pune. It is important to note that A(H1N1) strains were isolated in Pune during 2000 after a gap of 10 years. Since then, H3N2 influenza viruses have rapidly evolved and been the prominent strain in the influenza season, except the Covid pandemic period. Influenza B viruses are classified into lineages. At present, either B/Yamagata or B/Victoria viruses are in circulation. Therefore, unlike Covid, which was first identified in 2019, H3N2 has existed for several decades. Another major difference is that while Covid was caused by SARS CoV-2 virus, H3N2 is a subtype of influenza virus.


KEYWORDS: H3N2, Influenza, Influenza type A and Seasonal Influenza viruses, etc.




There are four types of seasonal influenza viruses — namely A, B, C and D. Influenza A viruses are classified into subtypes depending on the combinations of the proteins on the surface of the virus. Currently, subtype A(H1N1), also known as the swine flu, and A(H3N2) influenza viruses are circulating. Only influenza type A viruses are known to have caused pandemics. Influenza A H3N2 infection was more severe than A H1N1 or B in terms of fever, leukopenia, and C-reactive protein. H3N2 is a non-human influenza virus that normally circulates in pigs and has infected humans, according to the US Centre for Disease Control and Prevention (CDC).1


Figures at a Glance:

Confirmed influenza cases till March 9, ’23: 3,038

Total influenza-like illness cases: 9,67,749

Total severe acute respiratory illness cases: 15,826

Total H1N1 cases till February 28, 2023: 955




A 58-year-old woman died in Gujarat after contracting the H3N2 influenza virus, officials said. She was undergoing treatment at SSG hospital in Vadodara. With this, India’s death toll due to the H3N2 virus climbed to seven. The first reported H3N2 death in the country was an 82-year-old man in Karnataka’s Hassan district.


From January 2 to March 5, 451 cases of the H3N2 virus have been reported in the country, according to data shared by the health ministry.


India is seeing a spurt in Influenza cases, caused by H3N2 virus, which is highly contagious. According to the latest data available on IDSP-IHIP (Integrated Health Information Platform) till March 9, in 2023, India has seen a total of 3,038 lab-confirmed cases of various subtypes of influenza including H3N2. From January 2 to March 5, 451 cases of H3N2 have been reported in the country, according to data shared by the health ministry. India has also recorded its first two deaths due to seasonal influenza subtype H3N2, one each from Karnataka and Haryana. A respiratory illness, the virus spreads through infected droplets. In an advisory issued by the Indian Council of Medical Research (ICMR) last week, it urged people to wash hands with soap and water if symptomatic, wear masks and avoid crowded places, and cover their mouth and nose while sneezing and coughing.1



Seasonal influenza is characterized by a sudden onset of fever, cough (usually dry), headache, muscle and joint pain, severe malaise (feeling unwell), sore throat and a runny nose. The cough can be severe and can last two or more weeks. While fever, chills, cough and cold are common in both Covid and H3N2, shortness of breath can be experienced more in case of Covid than influenza.2



Patients who are not in a high-risk group should be managed with symptomatic treatment and are advised, if symptomatic, to stay home in order to minimize the risk of infecting others in the community. Treatment focuses on relieving symptoms of influenza such as fever. Young children and elderly people with co-morbidities are the most vulnerable groups in the context of seasonal influenza. Oseltamivir is the drug recommended by WHO. It is available through the public health system free of cost.


The ICMR recently issued an advisory asking people to avoid self-medication and use of antibiotics in this influenza outbreak.3



Annual seasonal influenza vaccines, also known as Quadrivalent Vaccines, are against H1N1 and H3N2 subtypes, and the Victoria and Yamagata lineages. Due to the constant evolving nature of influenza viruses, the WHO Global Influenza Surveillance and Response System (GISRS) — a system of National Influenza Centres and WHO Collaborating Centres around the world — continuously monitors the influenza viruses circulating in humans and updates the composition of influenza vaccines twice a year.3


Fighting H3N2 FLU:

Nutrition is Key:

Prachi Jain, HOD, Nutrition and Dietetics, CK Birla Hospital, Gurugram, shares, the three important Ms when coming to tackling a flu - Masks, Medicines, and Meals "To fight against any infection and flu, our immunity and immune system plays a crucial role to fight against the foreign body or infections. To strengthen our immune system, good and adequate nutrition is the key." While attaining strong immunity is a lifelong process dictated by a good lifestyle, it is important to pay attention to one's diet when one has the flu.4


H3N2 Influenza:

Food to have when down with Flu Prachi Jain shares a list of food to include when ill:

1.   Indian food plate which contains all the food groups in proper proportion i.e. – healthy and balanced diet.

2.   Eat enough protein –  0.8 to 1 gm per kg body weight at least. If there's any deficiency, the protein intake can increase to 1.2 to 1.5 gm after consulting a nutritionist/ doctor. Proteins help in muscle building, maintaining and repairing body tissues, helps in healing and speeds up the recovery process. Proteins you can have include milk and milk products, paneer, soya, tofu, lentils, nuts and boiled eggs.

3.   Vitamins and minerals – Include properly washed fresh seasonal fruits and vegetables as they are rich in antioxidants. You can boost your immune system by including these nutrients:


Vitamin A – Carrot, sweet potato, papaya, apricots 

Vitamin C – all citrus fruits like lemon, amla, tomatoes, oranges, sweet lime, etc

Vitamin E – Sunflower seeds, safflower seeds, almonds, and pistachios

Vitamin D – Fortified milk and milk products, mushrooms, eggs, fish

Zinc and Selenium – Seeds like chia seeds, pumpkin seeds, sunflower seeds, whole pulses, whole cereals, black til, eggs, fish

4.   Include Probiotics and Pre-biotics like curd, yoghurt, and fermented foods

5.   Indian Herbs and Spices – These have anti-inflammatory, anti-microbial, and anti- bacterial properties. Add things like tulsi, dry ginger, lemongrass, garlic, turmeric, black pepper, coriander, etc, to your diet.

6.   Omega 3 – Omega 6 – Include nuts and seeds like almonds, walnuts, chia seeds, flax seeds, pumpkin seeds and sunflower seeds.

7.   Hydration – Stay hydrated by including coconut water, lemonade, fresh homemade soups, buttermilk and green tea.  Maintain 2- 2.5 litre of fluid intake on a daily basis.4


Food To Stay Away From If You Have Flu:

A list of food to avoid when you have the flu:

1.     Avoid carbonated drinks, cold drinks, squashes, etc

2.     Avoid roadside, raw, stale food to prevent infection

3.     Avoid fried and deep-fried food

4.     Avoid bakery food items, maida which includes junk foods like pizza, pasta, burgers, and fries

5.     Avoid processed foods like cheese, and mayonnaise

6.     Avoid alcohol

7.     Quit smoking and tobacco


Precautionary steps recommended by leading health professionals wear masks, at the very least, in areas that are extremely vulnerable, such as on public transportation, in hospitals, at airports, on trains, and elsewhere


Avoid visiting crowded areas without wearing a mask


·       To reduce the risk of infection, wash hands with soap or sanitizer before using any public transportation or eating

·       Flu vaccinations, which must be administered yearly to help build immunity

·       As antibiotics only combat bacteria and not viruses, they should not be used to treat the flu.5


H3N2 virus in India: From masks to personal hygiene, check tips to prevent flu infection


The differences in clinical features between influenza A H1N1, A H3N2:

Gastrointestinal symptoms such as nausea, epigastralgia, and diarrhoea were prominent in influenza B. Myalgia was common in all groups. Influenza A H3N2 infection was more severe than A H1N1 or B in terms of fever, leukopenia, and C-reactive protein.6



As concerns mounted and some people wondered whether H3N2 could possibly turn out to be another Covid, pulmonologist Anurag Agrawal said he doesn’t expect to see a massive wave. Experts also suggested the virus is not life-threatening in normal circumstances. H3N2 is a non-human influenza virus that normally circulates in pigs and has infected humans but experts said the seasonal flu which is usually detected in India during January - March and then after Monsoon, will see a decline after March. The government has recommended to follow Covid protocols and hygiene practices to avoid infection.6



1.   https://www.indiatoday.in/india/story/h3n2-influenza-virus-first-death-gujarat-seven-in-india-2346356-2023-03-14

2.   https://pubmed.ncbi.nlm.nih.gov/12753540/#:~:text =Gastrointestinal%20symptoms%20such%20as%20nausea,%2C%20and%20C%2Dreactive%20protein.

3.   https://pubmed.ncbi.nlm.nih.gov/12025254/

4.   https://zeenews.india.com/health/exclusive-h3n2-influenza-down-with-flu-list-of-foods-to-eat-and-avoid-check-nutritionists-advice-2583352

5.   https://www.dnaindia.com/india/report-h3n2-virus-in-india-from-masks-to-personal-hygiene-check-tips-to-prevent-flu-infection-h3n2-cases-in-india-3029815

6.   https://www.hindustantimes.com/india-news/is-h3n2-virus-life-threatening-could-it-be-another-covid-experts-respond-101678584622228.html




Received on 27.03.2023         Modified on 29.05.2023

Accepted on 24.06.2023       ©A&V Publications All right reserved

A and V Pub IntJ. of Nursing and Medical Res. 2023; 2(2):56-59.

DOI: 10.52711/ijnmr.2023.15