Some children in my practice are not up to date on their immunizations, and pertussis is circulating in our community. Can you guide me in determining how to make the decision about which vaccine to choose?

You should use DTaP to catch up children younger than age 7 years. In addition, ACIP recommends giving one dose of Tdap to children age 7–10 years who were not fully vaccinated against pertussis before their seventh birthday. Children age 7–10 who require more than one dose of tetanus-containing vaccine to be up to date with diphtheria or tetanus immunization may be given either Td or Tdap for doses needed after the initial Tdap dose. Although this is an off-label use of the vaccines, it’s important that you vaccinate these unvaccinated or undervaccinated older children with Tdap as well as any other adolescent or adult who hasn’t received Tdap previously.