 Hello, I am Dr. Bhaskar Shani, Head of the Department of Pediatrics and Chief of Division of Pediatric Infectious Diseases at Manipal Hospital, Bangalore. There are various types of vaccines. For example, there is a killed vaccine, then live attenuated vaccine, then the biological vaccines, then there are some DNA vaccines. The killed vaccine, the bacteria or virus whichever is there, we kill it and that killed the proteins or whatever content of the particular organism will produce, when it is administered to the body will produce immunity. There are other vaccines which are live, live in the sense they are attenuated, attenuated in the sense their disease producing capacity is reduced, but they are able to produce the protective antibodies in the blood. So as a consequence, the baby is protected against the disease, but protected against the doesn't cause any ill effects.