An 85-year-old man in Karnataka has become the first person to die due to the H3N2 variant of the influenza virus in the state. The other death in India due to H3N2 was reported from Haryana. More than 90 cases of H3N2 have been detected across the country, and eight H1N1 cases have also been reported. Over the past few weeks, there has been an increase in the number of flu cases in India, causing concern. What is H3N2 and is there a need to worry?
The H3N2 variant (also called H3N2v) is one of the variants of the influenza virus that causes seasonal flu, which causes acute respiratory infection. In general, influenza viruses are categorised into four types — Type A, Type B, Type C and Type D. The Type A and B viruses are the ones that cause seasonal illnesses.
Type A virus is classified into H1N1 and H3N2 influenza viruses. Type B viruses are not classified but broken down into lineages; Type C is detected less frequently and causes mild infections; and Type D viruses are detected primarily in cattle and not found to have infected humans.
When the influenza viruses circulate in pigs and later detected in humans, they are called ‘variants’. H3N2 and H1N1 were detected for the first time in pigs in the United States in 2010, and in 2011 in humans. In July 2011, 12 persons were reported to have contracted the H3N2v infection and it rose to 309 in 2012. Since then, there have been multiple outbreaks of viral illness.
According to the World Health Organisation (WHO), most infected people recover from fever and other symptoms within a week. But people at high risk – including “pregnant women, children under 59 months, the elderly, individuals with chronic medical conditions (such as chronic cardiac, pulmonary, renal, metabolic, neurodevelopmental, liver or hematologic diseases) and individuals with immunosuppressive conditions (such as HIV/AIDS, receiving chemotherapy or steroids, or malignancy)” – can require hospitalisation.
Usually, any seasonal influenza virus spreads through the air and through direct contact. The spread increases in closed spaces like schools and nursing homes. Washing hands properly, regularly, wearing masks, avoiding contact with those infected and closed spaces can prevent the virus from spreading. Further, annual vaccination, commonly called ‘flu shots’ have proved effective against the virus.
The US-based Centers for Disease Control and Prevention (CDC) has listed some precautionary measures to prevent the viral spread.
The Indian Medical Association (IMA) has issued an advisory stating that patients need only symptomatic treatment and antibiotics should not be prescribed unnecessarily.
Fever cases on rise - Avoid Antibiotics pic.twitter.com/WYvXX70iho
— Indian Medical Association (@IMAIndiaOrg) March 3, 2023