Vaccination schedules are typically divided by age group and are designed to optimize the immune response in children. For instance, the CDC's immunization schedule for children from birth to 18 years includes vaccines for Hepatitis B, Rotavirus, DTaP (Diphtheria, Tetanus, and Pertussis), Hib (Haemophilus influenzae type b), PCV (Pneumococcal conjugate), and many others. Pediatricians work closely with parents to ensure these vaccines are administered at the appropriate times.