**Core Concept**
Tetanus prevention in a patient with a lacerated wound involves administering tetanus toxoid or tetanus immunoglobulin to ensure adequate immunity against tetanus toxin. This is crucial in individuals with a history of incomplete or uncertain vaccination.

**Why the Correct Answer is Right**
The patient has a history of taking a complete course of tetanus toxoid with a booster dose 4 years ago. However, considering the wound is lacerated and there is tissue damage, the patient may not have adequate immunity against tetanus toxin. The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recommend administering tetanus toxoid (Tdap) as a booster dose in individuals with uncertain or incomplete vaccination history. In this case, since the patient's last booster dose was 4 years ago, it is advisable to administer another dose of tetanus toxoid to ensure adequate immunity.

**Why Each Wrong Option is Incorrect**
**Option A:** Administering tetanus immunoglobulin (TIG) alone is not sufficient for individuals with a history of vaccination. TIG provides immediate protection but does not stimulate an immune response.
**Option B:** Not administering any tetanus prophylaxis is not recommended, as it may lead to tetanus infection in the event of inadequate immunity.
**Option C:** Repeating Tdap immediately may not be necessary, as the patient has a history of completing the primary vaccination series and has received a booster dose 4 years ago.

**Clinical Pearl / High-Yield Fact**
In patients with uncertain or incomplete vaccination history, administer tetanus toxoid (Tdap) as a booster dose to ensure adequate immunity against tetanus toxin. This is especially crucial in individuals with wounds that are dirty, deep, or caused by a rusty object.

**Correct Answer:** D. Administer Tdap as a booster dose.