Babies are born with protection against some diseases because their mothers pass antibodies (proteins made by the body to fight disease) to them before birth. Breastfed babies continue to get more antibodies in breast milk. But in both cases, the protection is temporary.
Immunization (vaccination) is a way to create immunity to (protection from) some diseases. Sometimes this is done by using small amounts of a killed or weakened germs that causes the disease. Other times the vaccine is simply a small piece of the germ, such as a protein or a piece of its genetic material. Once injected, this 'foreign' material stimulates "immunity" naturally, which is long lasting and sustainable through periodic vaccinations as suggested by your Doctor/Paediatrician.
Vaccinations are responsible for healthy children. These children are able to fight diseases with ease, making them "Strong".
If you want your child to live life with his/her head held high, vaccinate them timely and gift them a "Healthy Life".