Study finds multiple dengue virus strains circulating together in India, Pg12

Key Highlights:

• A two-year nationwide surveillance study by the Indian Council of Medical Research’s (ICMR) Virus Research and Diagnostic Laboratory (VRDL) network found all four dengue virus serotypes circulating simultaneously across India.
• DENV-2 was identified as the predominant serotype, accounting for over half of all infections.
• Approximately 7% of patients in the study were infected with two or more dengue serotypes concurrently.
• Concurrent infections were associated with a higher likelihood of severe dengue manifestations, including low platelet counts and bleeding complications.
• India recently approved its first dengue vaccine, Qdenga, for individuals aged 4 to 60 years, which received regulatory clearance for import and sale.

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Detailed Insights:

• The study, titled “Pan-India Molecular Surveillance of Dengue Serotypes, 2023-2025”, analyzed 6,889 laboratory-confirmed dengue samples from 45 laboratories across 25 States and Union Territories.
• Eight States and Union Territories reported the presence of all four serotypes, while 15 reported three circulating simultaneously.
• The widespread co-circulation of multiple serotypes indicates dengue hyper-endemicity in the country.
• Patients with concurrent infections were more prone to severe joint pain in addition to other severe symptoms.
• India currently does not include a dengue vaccine in its Universal Immunisation Programme (UIP).
• The Central Drugs Standard Control Organisation (CDSCO) granted marketing authorization for Qdenga, manufactured by Takeda GmbH, Germany.
• Continuous surveillance of serotypes is critical because vaccine effectiveness varies against different dengue strains, and shifts in dominant serotypes can influence outbreak intensity and vaccine performance.

Scientific/Technical Concepts Involved:

• Dengue Serotypes: Four distinct types of the dengue virus (DENV-1, DENV-2, DENV-3, DENV-4) that can cause the disease.
• Hyper-endemicity: A state where multiple serotypes of a disease-causing agent continuously circulate within a geographic area, increasing the risk of severe illness upon subsequent infections.
• Vector-borne disease: An illness transmitted to humans or other animals by blood-feeding arthropods, such as mosquitoes in the case of dengue.