The objective for this study is to characterize the safety profile of PENTACEL® vaccine for identification of potential vaccine-related adverse events not currently associated with PENTACEL® vaccine administration.

The study will be conducted at Kaiser Permanente Northern California and will commence with first use of licensed PENTACEL® vaccine within that organization.

Vaccination databases will be reviewed to identify Diphtheria and tetanus toxoid with acellular pertussis (DTaP) vaccinations of accrued subjects. Medical encounter, emergency room, hospitalization, laboratory, state death reporting, and related databases will be reviewed to identify medical care events.

Inclusion Criteria:

• Receipt of DTaP vaccine during the study period by a previously unvaccinated child

Exclusion Criteria:

• None

Receipt of DTaP vaccine during the study period by a previously unvaccinated subjects