Ahead of dengue vaccine rollout, all 4 strains found in circulation

India's first nationwide dengue virus mapping found all four serotypes (DENV-1, DENV-2, DENV-3, DENV-4) circulating in eight states and UTs: Andhra Pradesh, Gujarat, Haryana, Madhya Pradesh, Maharashtra, Rajasthan, Tamil Nadu, and West Bengal.

DENV-2 was the dominant strain, accounting for 51% of infections, followed by DENV-3 (13%), DENV-1 (7%), and DENV-4 (1%).

About 7% of patients had concurrent infections with multiple serotypes, linked to higher risk of thrombocytopenia, haemorrhagic manifestations, and arthralgia.

The study, led by ICMR-National Institute of Virology, Pune, analyzed 6,889 samples from 45 labs across 25 states and UTs between 2023 and 2025.

Researchers said continuous molecular surveillance is essential to guide vaccine strategy, as vaccine efficacy varies against different serotypes.