Some vaccine-preventable diseases, like pertussis (whooping cough) and chickenpox, remain common in the United States.
On the other hand, other diseases prevented by vaccines are no longer common in this country because of vaccines. However, if we stopped vaccinating, even the few cases we have in the United States could very quickly become tens or hundreds of thousands of cases.
Even though many serious vaccine-preventable diseases are uncommon in the United States, some are common in other parts of the world. Even if your family does not travel internationally, you could come into contact with international travelers anywhere in your community.
Kids that are not fully vaccinated and are exposed to a disease can become seriously sick and spread it through a community.