Study of DAPTACEL® Administered as a 5th Dose in 4 to 6-Year-Old Children Previously Immunized With PENTACEL™

Inclusion Criteria : * Aged ≥ 4 years and 6 years. * Signed and dated Investigational Review Board-approved informed consent from a parent or legally authorized representative. * Judged to be in good health on the basis of reported medical history and physical examination. * Able and willing to attend the scheduled visits and to comply with the study procedures. * Has documented complete infant series and 4th dose in Study 494-01 or Study 494-03, consisting of four previous administrations of PENTACEL™. Exclusion Criteria : * Received a 5th dose of DTaP-containing vaccine scheduled at 4 to 6 years of age. * Serious underlying chronic disease, including, but not limited to: * Diabetes mellitus; malignancy; cardiopulmonary disease; renal, endocrinologic, or hepatic dysfunction; or hematologic disorder; or * Unstable or evolving neurologic disorders that may predispose the subject to seizures or neurologic deterioration. * Known or suspected primary or acquired disease of the immune system. * Administration of immune globulin or other blood products within the last 3 months, or injected or oral corticosteroids or other immunomodulatory therapy within 6 weeks of the study vaccine. Individuals on a tapering dose schedule of oral steroids lasting \<7 days may be included in the trial as long as they have not received more than 1 course within the last 2 weeks prior to enrollment. * Had allergy shots started or had changes in regimen or dosing of allergy shots within the last 4 weeks. * Receipt of any other vaccine within the past 30 days, or planning to receive another vaccine within 30 days before the Visit 2 blood draw, with the exclusion of M-M-R®II and IPV. * Any other condition which, in the opinion of the Investigator, would pose a health risk to the subject or interfere with the evaluation of the vaccine. * Enrolled in another vaccine trial. * Personal history of physician-diagnosed or laboratory-confirmed pertussis disease within the past 30 months. * Known or suspected allergy to any of the vaccines or vaccine components intended for use in this study. Temporary contraindications: * A subject who meets either of the following criteria at the time of planned vaccination will have enrollment deferred until complete resolution of symptoms: Oral temperature ≥ 100.4°F (≥ 38.0ºC) (Note: A tympanic thermometer should not be used). * Any moderate or severe acute illness with or without fever.