Question

why infants given vaccination​

Answer 1

To prevent them from any future diseases

Answer 2

Here's your ans mate

If your immune system – which is composed of all number of cells, glands, organs, and fluids – does not recognize a foreign germ (known as an antigen), it will send proteins called antibodies out to fight those invasive germs. When the antibodies are able to overpower and effectively prevent the antigen from entering and affecting the body, then immunity begins to develop. But if the antigen is too powerful – as in the case with many diseases that are not just common germs – then the antibodies will not know how to deal with the antigen and will be unable to prevent it from compromising your health.

I hope it helps.