Following the recommended vaccination schedule is important because it helps protect infants and children against infections that can be prevented. The schedule below is based on the one recommended by the American Academy of Pediatrics and the Centers for Disease Control and Prevention (see Immunization Schedules for Infants and Children ). The schedule indicates which vaccines are needed, at what age, and how many doses (indicated by the numbers in the symbols). There is a range of acceptable ages for many vaccines. A child's doctor can provide specific recommendations, which may vary depending on the child's known health conditions and other circumstances. Often, combination vaccines are used, so that children receive fewer injections. If children have not been vaccinated according to the schedule, catch-up vaccinations are recommended, and parents should contact a doctor or health department clinic to find out how to catch up. Parents should report any side effects after vaccinations to their child's doctor. For more information about this schedule, parents should talk to a doctor or visit the Centers for Disease Control and Prevention's National Immunization Program web site.