SCIENTIFIC THINKING Pertussis (whooping cough) is caused by a bacterial infection, and symptoms include an intense cough that lasts for weeks, sometimes leading to pneumonia and death. A complete vaccination against pertussis requires five doses, completed by age 5. A pertussis outbreak occurred in California in 2010, and a news article reported the following: 'Among fully immunized kids, there were about 36 cases for every 10,000 children two to seven years old, compared to 245 out of every 10,000 kids aged eight to twelve.' Propose an explanation for these data and a public health solution based on your explanation.