 Hello, I am Dr. Bhaskar Ashanayi, Head of the Department of Pediatrics and Chief of Division of Pediatric Infectious Diseases at Manipal Hospital, Bangalore. Herd immunity is something like this. When we give the vaccine, the child is protected. Meantime, some amount of virus can spread in the community and the others who are not vaccinated also may be protected to some extent. That means the protective effectiveness of that vaccine spreads into the community. That is called as herd immunity. And that is one more way of boosting the immunity of the society in general towards the vaccination. Some children who are not vaccinated also may get protection because of this.