Concerns Over Dengue Vaccine DengiAll:
Concerns have emerged about India’s forthcoming dengue vaccine DengiAll, following reports of severe adverse events during Brazil’s vaccination campaign with Butantan-DV, highlighting antibody-dependent enhancement (ADE) risks, tetravalent vaccine efficacy, and the need for robust monitoring.Vaccine Type: Both DengiAll (India) and Butantan-DV (Brazil) are live-attenuated tetravalent dengue vaccines, combining four weakened dengue virus serotypes (DENV-1, 2, 3, 4).All four dengue serotypes are prevalent in Brazil and India, and their envelope proteins differ enough to require protection against each serotype separately; merely mixing four weakened viruses does not automatically guarantee balanced immunity.Dengue vaccination can produce type-specific antibodies, which block one serotype effectively, and cross-reactive antibodies, which recognise all four serotypes but protect only when present at sufficiently high levels.When cross-reactive antibody levels fall, they may enhance rather than block dengue infection, leading to severe and potentially fatal dengue; this phenomenon is called antibody-dependent enhancement and is treated as a serious adverse event.
