Question:medium
What is the amount of diphtheria toxoid present in the pediatric DT vaccine?
What is the amount of diphtheria toxoid present in the pediatric DT vaccine?
Show Hint
Pediatric DT is full strength; adult dT drops to about 2 Lf.
Updated On: Jun 24, 2026
- 5 Lf
- 10 Lf
- 15 Lf
- 25 Lf
Show Solution
The Correct Option is D
Solution and Explanation
Step 1: Recall that diphtheria toxoid strength is quoted in Lf units and that there are two grades, a high-dose pediatric one and a low-dose adult one.
Step 2: The capital-D, capital-T pediatric DT (and the pediatric DPT) carries the full 25 Lf of diphtheria toxoid, because young children tolerate and need the larger antigen load to prime immunity.
Step 3: Contrast this with the small-d adult dT given to those over 12 years, which drops the diphtheria toxoid to about 2 Lf to limit hypersensitivity reactions in already-sensitised individuals.
Step 4: Remember the supporting facts: aluminium hydroxide or phosphate is the adjuvant, thiomersal the preservative, the cold-chain range is +2 to +8 degrees C, and the vaccine must never be frozen. So the pediatric DT diphtheria content is the highest value offered.
\[\boxed{\text{25 Lf}}\]
Step 2: The capital-D, capital-T pediatric DT (and the pediatric DPT) carries the full 25 Lf of diphtheria toxoid, because young children tolerate and need the larger antigen load to prime immunity.
Step 3: Contrast this with the small-d adult dT given to those over 12 years, which drops the diphtheria toxoid to about 2 Lf to limit hypersensitivity reactions in already-sensitised individuals.
Step 4: Remember the supporting facts: aluminium hydroxide or phosphate is the adjuvant, thiomersal the preservative, the cold-chain range is +2 to +8 degrees C, and the vaccine must never be frozen. So the pediatric DT diphtheria content is the highest value offered.
\[\boxed{\text{25 Lf}}\]
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