## **Core Concept**
The management of non-immunized diphtheria contacts involves several strategies to prevent the spread of the disease. Diphtheria is a bacterial infection caused by Corynebacterium diphtheriae, and it can lead to severe respiratory and cardiac complications. Contacts of diphtheria patients are at risk of developing the disease, especially if they are not immunized.

## **Why the Correct Answer is Right**
Prophylactic penicillin is indeed a part of managing diphtheria contacts to eradicate the carrier state. Daily throat examinations and throat swab culture for contacts are also crucial for early detection and treatment of potential cases. A single dose of toxoid, however, is not sufficient for immediate protection against diphtheria. Full immunization requires multiple doses of diphtheria toxoid.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Prophylactic penicillin is actually a correct approach for managing diphtheria contacts, especially to eliminate the carrier state of C. diphtheriae. So, this option is incorrect as an "except" choice.
- **Option C:** Daily throat examinations are important for early detection of diphtheria in contacts. This is a correct approach, making it an incorrect choice for "except".
- **Option D:** Throat swab culture is a diagnostic tool used to identify carriers of C. diphtheriae among contacts. This is also a correct approach, making it incorrect for "except".

## **Why Option B is Correct as the Answer**
- **Option B:** A single dose of toxoid does not provide immediate or adequate protection against diphtheria. For effective immunization, multiple doses are required. Therefore, as an immediate measure for non-immunized contacts, a single dose of toxoid is not sufficient.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that for immediate protection against diphtheria, especially in contacts, **prophylactic antibiotics** like penicillin or erythromycin are used, and **full immunization** with diphtheria toxoid is essential for long-term protection.

## **Correct Answer: B. Single dose of Toxoid**