I need to know how to catch-up a child who is 12 years old and received 1 dose of DTaP vaccine at age 2 years and a dose of Tdap at age 11 years.

This child needs to complete the primary series with 1 dose of Td or Tdap, administered no earlier than 6 months after the Tdap dose given at age 11 years. After that, the child needs a booster dose of Td or Tdap every 10 years. An easy way to determine how to catch up a child is to consult “Recommended Immunization Schedules for Persons Aged 0 Through 18 Years, U.S.” The schedule is approved by CDC, AAP, and AAFP and is released early in each calendar year. It includes a catch-up schedule for children who have fallen behind (see www.cdc.gov/vaccines/schedules/index.html).