The study focuses on the viral illnesses measles, mumps and rubella, which can be prevented by a single injection called the MMR vaccine. This vaccine contains weakened (live attenuated) viruses that stimulate the body’s defense without causing the diseases. In the trial, infants receive either the vaccine or a placebo at six months of age, followed by the routine childhood dose at four years.
The purpose of the study is to compare the long‑term immune response after an early dose of the vaccine versus the placebo. Researchers will look at the level of protection by measuring specific proteins, known as neutralising antibodies, that can block the measles virus.
After the initial injection, children continue with the normal vaccination schedule. Several years later, a small blood sample is taken to assess how many protective antibodies are present, using a laboratory method that counts how well the blood can stop the virus from growing. This follow‑up helps determine whether giving the vaccine earlier influences lasting immunity.



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