This depends on the contraindication or precaution the person had to DTaP.
The contraindications are (1) severe allergic reaction (e.g., anaphylaxis after a previous dose or to a vaccine component) and (2) encephalopathy within 7 days of a previous dose of DTaP or DTP; in these cases, give Td instead of Tdap.
The precautions for which Tdap vaccination may be delayed or for which the balance of individual risks and benefits should be weighed are
- Moderate or severe acute illness (defer until recovered);
- History of an Arthus-type hypersensitivity reaction following a previous dose of tetanus or diphtheria toxoid-containing vaccines, including MenACWY-D or MenACWY-TT (Menactra or MenQuadfi, Sanofi Pasteur) (defer vaccination until at least 10 years have elapsed since the last tetanus-toxoid-containing vaccine);
- Guillain-Barré syndrome (GBS) 6 weeks or sooner after a previous dose of tetanus toxoid-containing vaccine; and
- Progressive or unstable neurologic disorder, uncontrolled seizures or progressive encephalopathy until a treatment regimen has been established and the condition has stabilized.
ACIP has published a Guide to Vaccine Contraindications and Precautions in its “General Best Practice Guidelines for Immunization”, available at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/contraindications.html.