How does QDENGA, the 1st dengue vaccine approved by India, work?

QDENGA vaccine contains attenuated versions of 4 dengue virus serotypes. These versions cannot cause the disease, but they teach the immune system to defend the body against the virus. When a person is later exposed to the virus, the immune system recognises it and quickly makes many more antibodies, which then neutralise the virus before it can cause dengue disease.