What is the dose of Tdap (tetanus, diphtheria, and pertussis) vaccine for children and adults?

Dosage of Tdap for Children and Adults

The standard dose of Tdap (tetanus, diphtheria, and pertussis) vaccine is 0.5 mL administered intramuscularly for both children and adults. 1

Dosage by Age Group

Children Under 7 Years

• DTaP (not Tdap) is the appropriate vaccine for children under 7 years of age 1
• DTaP dose is 0.5 mL administered intramuscularly 1
• Preferred injection site:
  • For infants and children through age 2 years: anterolateral aspect of the thigh 1
  • For children aged ≥3 years: deltoid muscle 1

Children 7-10 Years

• Tdap dose is 0.5 mL administered intramuscularly, preferably into the deltoid muscle 1
• Only one dose of Tdap is recommended at this time for children 7-10 years with incomplete pertussis vaccine history 1
• If further doses of tetanus-containing vaccine are required, they are given according to catch-up schedule 1

Adolescents (11-18 Years)

• Tdap dose is 0.5 mL administered intramuscularly, preferably into the deltoid muscle 1
• Only one dose of Tdap is recommended for routine immunization during adolescence 2

Adults (≥19 Years)

• Tdap dose is 0.5 mL administered intramuscularly, preferably into the deltoid muscle 1
• Only one dose of Tdap is recommended for adults 3
• For adults aged ≥65 years, Boostrix (approved for use in persons aged ≥10 years) is preferred over Adacel (approved for use in persons aged 10-64 years), but either vaccine is considered valid and immunogenic 1, 3

Administration Guidelines

Timing and Intervals

• After the initial Tdap dose, subsequent tetanus and diphtheria protection should be maintained with Td boosters every 10 years 3
• There is no minimum interval required between receipt of a tetanus toxoid-containing vaccine and Tdap when Tdap is otherwise indicated 1

Special Considerations

• DTaP is not indicated for persons aged ≥7 years 1
• If DTaP is administered inadvertently to a fully vaccinated child aged 7-10 years, this dose should be counted as the adolescent Tdap dose 1
• If Tdap is administered inadvertently instead of DTaP as any of the first 3 doses in children under 7 years, the dose should not be counted as valid, and a replacement dose of DTaP should be administered 1

Common Pitfalls to Avoid

• Avoid confusing DTaP (for children under 7 years) with Tdap (for individuals 7 years and older) as they contain different antigen amounts 1
• Tdap contains lower amounts of diphtheria toxoid and lower amounts of pertussis antigens compared to DTaP 1
• Review product labels before administering vaccines as packaging might appear similar 1
• Avoid unnecessary additional doses of Tdap as only one dose is currently recommended for routine immunization 2
• Be aware that large injection site reactions are more common with DTaP booster doses in children 4-6 years of age compared to Tdap 4

By following these dosage recommendations and administration guidelines, healthcare providers can effectively protect patients against tetanus, diphtheria, and pertussis while minimizing adverse reactions.