Across India, an outbreak of a respiratory illness with symptoms of cold, sore throat and fever accompanied by fatigue has been observed since December 2022 and January 2023.
- The Indian Council of Medical Research (ICMR) confirmed that Influenza Sub-type H3N2 has been causing this illness.
- It further warned that the virus appeared to lead to more hospitalisations than other Influenza subtypes.
- There are four types of seasonal influenza viruses, types A, B, C and D.
- Influenza A and B viruses circulate and cause seasonal epidemics of disease. Influenza A viruses are the only influenza viruses known to cause flu pandemics (i.e., global epidemics of flu disease).
- H3N2 virus is a type of influenza virus called the influenza A virus.
- It is a respiratory viral infection that causes illnesses every year. This subtype of influenza A virus was discovered in 1968 in humans.
- The virus derives from types of protein strains of the influenza A virus – hemagglutinin (HA) and neuraminidase (NA).
- HA has over 18 different subtypes, each numbered H1 to H18 while NA has 11 different subtypes, each numbered N1 to N11.
- The H3N2 is a combination of the two protein strains of the influenza A virus.
- The symptoms of the H3N2 virus include cough, runny nose or congested nose, sore throat, headaches, body aches, fever, chills, fatigue, diarrhoea, vomiting and breathlessness.