Another disease making a big comeback, because of the anti-vaccination craziness spread by irresponsible people like Jenny McCarthy: whooping cough.

Children who aren’t vaccinated against whooping cough are 23 times more likely to develop the disease than children who get all of their shots on time, a new study shows.

Whooping cough, or pertussis, has been making a resurgence in recent years as more parents decide not to vaccinate their children, says Jason Glanz, author of a study in today’s Pediatrics. In a study of 751 children enrolled in Kaiser Permanente of Colorado, one in 20 children who skipped the vaccine developed whooping cough, compared with one in 500 vaccinated children. In all, 11% to 12% of pertussis cases were in unvaccinated children.

Though more than 90% effective, the vaccine doesn’t protect everyone, says Sean O’Leary, an infectious-disease fellow at Children’s Hospital in Denver.

That’s why vaccinating all children is crucial to creating “herd immunity” for the entire community, including newborns who are too young to be immunized, O’Leary says.