Recommended Dose of Tetanus Toxoid for a 5-Month-Old Infant
The recommended dose of tetanus toxoid for a 5-month-old infant is 0.5 mL of DTaP vaccine administered intramuscularly into the anterolateral aspect of the thigh. 1
Standard Dosing
- All DTaP vaccines are administered as a 0.5 mL dose intramuscularly, regardless of the child's weight or size. 1
- Fractional doses (less than 0.5 mL) should never be administered, as they do not provide adequate protection. 1
- The preferred injection site for infants and children through age 2 years is the anterolateral aspect of the thigh. 1
Routine Vaccination Schedule Context
At 5 months of age, this infant should be receiving their third dose of the DTaP primary series:
- The standard DTaP schedule consists of doses at 2,4, and 6 months of age for the primary series. 1
- A 5-month-old would typically be due for or have recently received the 4-month dose (second dose). 1
- The third dose should not be administered before 14 weeks (approximately 3.5 months) of age. 1
- If an accelerated schedule is needed, a minimum interval of 4 weeks should occur between doses. 1
Critical Clinical Considerations
Age-appropriate vaccine selection is essential:
- DTaP (not Tdap, Td, or tetanus toxoid alone) must be used for children under 7 years of age. 1, 2, 3
- DTaP provides necessary protection against diphtheria and pertussis in addition to tetanus. 2, 3
- Using the wrong vaccine formulation for age is the most common error in tetanus vaccination. 2
Vaccine interchangeability:
- Whenever feasible, the same manufacturer's DTaP product should be used for all doses in the series. 1
- However, vaccination should not be deferred if the specific DTaP brand previously administered is unavailable or unknown. 1
- Any licensed DTaP vaccine may be used to complete the vaccination series. 1
Administration Technique
- DTaP may be administered simultaneously with other vaccines at different anatomical sites. 1
- At 5 months of age, the infant may be receiving other vaccines such as IPV, Hib, pneumococcal conjugate, and hepatitis B vaccines concurrently. 1
- Each vaccine should be given with a separate syringe at a different injection site. 1
Common Pitfall to Avoid
Never administer a reduced dose or split the 0.5 mL dose across multiple injections. The entire 0.5 mL must be given as a single intramuscular injection to ensure adequate immune response. 1 This is a fixed dose that does not vary based on the infant's size or weight.