Whooping cough is a very dangerous disease, especially for infants. The risk of suffering and death caused by whooping cough is far greater than the possible side effects of the vaccine. A child who has not been immunized against pertussis has a chance of 1 in 3000 of getting whooping cough. In contrast, a child who got the vaccine has a chance of 1 in 2 million of having neurological damage with the vaccine. The risk of children getting pertussis increases if fewer children are immunized.