Ring vaccination — DTM&H MCQ

Correct answer: B — Ring vaccination around the case

The correct answer is B, ring vaccination around the case. When a confirmed Ebola case is identified early with vaccine stock and trained teams available, and rapid contact tracing to contacts and contacts of contacts is feasible, ring vaccination is the evidence based, resource appropriate response. This approach vaccinates the case's contacts and their onward contacts, creating an immunological barrier that interrupts the transmission chain around the index case rather than attempting to vaccinate an entire population. It relies precisely on the two capabilities stated in the stem, an available vaccine and trained teams able to trace contacts rapidly, which is exactly the operational infrastructure validated in ring vaccination trials such as Ebola ca Suffit, Guinea 2015. Ring vaccination should run alongside isolation and safe burial, but among the listed options it is the specific prophylactic tool matched to this scenario. Why the other options are wrong: A. Nationwide infant BCG campaign: BCG protects against tuberculosis and has no activity against Ebola virus, and a nationwide infant campaign is illogical for containing an acute point-source outbreak with known contacts. D. Mass yellow fever vaccine in contacts alone: yellow fever vaccine targets a different, mosquito-borne flavivirus and provides no protection against Ebola virus disease. C. Indoor residual spraying: this is a vector control measure for mosquito-borne disease; Ebola spreads by direct contact with body fluids, so spraying is mechanistically irrelevant. E. Universal antibiotics: Ebola is a viral haemorrhagic fever, antibiotics have no antiviral activity, and blanket use would only drive resistance without limiting transmission. Key point: Ring vaccination, immunising contacts and contacts of contacts around a confirmed case, is the targeted prophylactic strategy of choice once vaccine supply and trained contact tracing teams are available in an Ebola outbreak.

Reference: World Health Organization, Ebola vaccines (Q&A), ring vaccination strategy defined as vaccinating close contacts and potential contacts (contacts of contacts) of a confirmed or probable case; https://www.who.int/news-room/questions-and-answers/item/ebola-vaccines