What is a recommended prophylaxis for close contacts of a diphtheria case?

What is a recommended prophylaxis for close contacts of a diphtheria case?

• A. DTaP vaccination only
• B. Erythromycin x 3 days
• C. Penicillin G x 1 dose
• D. Erythromycin x 7-10 days or PCN benzathine G x 1 dose

Answer: (D)

Close contacts of a diphtheria case need antibiotic prophylaxis to eradicate any carriage and prevent transmission, regardless of vaccination status. The documented options are either a macrolide taken for 7–10 days or a single dose of long-acting penicillin (benzathine penicillin G). Erythromycin for 7–10 days ensures the bacteria are cleared from the pharynx, while a single dose of benzathine penicillin G provides sustained levels to cover carriage with just one administration. Shorter courses, like 3 days, are insufficient for eradication, and a booster vaccine alone does not treat exposure or carriage. A single non-benzathine penicillin G dose isn’t the standard prophylaxis option, whereas benzathine penicillin G as a single dose is an accepted alternative. Therefore, the best choice matches these recommended prophylaxis regimens.

Close contacts of a diphtheria case need antibiotic prophylaxis to eradicate any carriage and prevent transmission, regardless of vaccination status. The documented options are either a macrolide taken for 7–10 days or a single dose of long-acting penicillin (benzathine penicillin G). Erythromycin for 7–10 days ensures the bacteria are cleared from the pharynx, while a single dose of benzathine penicillin G provides sustained levels to cover carriage with just one administration. Shorter courses, like 3 days, are insufficient for eradication, and a booster vaccine alone does not treat exposure or carriage. A single non-benzathine penicillin G dose isn’t the standard prophylaxis option, whereas benzathine penicillin G as a single dose is an accepted alternative. Therefore, the best choice matches these recommended prophylaxis regimens.