Which disease is almost certain to cause death without postexposure prophylaxis?

Rabies is a viral disease that affects the central nervous system and is almost universally fatal once clinical symptoms appear. The virus is usually transmitted through the bite of a rabid animal, and if an individual is exposed, postexposure prophylaxis (PEP) is crucial to prevent the onset of the disease. PEP consists of a series of rabies vaccinations, and if administered promptly after exposure, it is highly effective in preventing rabies from developing.

The progression of rabies is particularly concerning because, once symptoms manifest, the disease is nearly always fatal, typically leading to death within a few weeks. This urgency highlights the critical nature of timely intervention with postexposure prophylaxis following any potential rabies exposure.

In contrast, while the other diseases listed can have serious health implications, they do not have the same level of inevitability in terms of mortality without treatment as rabies does. For example, hepatitis B can lead to severe liver disease but is typically managed effectively upon diagnosis. Measles can cause complications and may result in death, but there are vaccines available that can prevent the disease entirely. Meningococcal disease can progress rapidly and can be fatal, but again, there are effective vaccines and treatments available that can save lives.