What diseases currently have no vaccines?

• A. Hep A and HIV
• B. Hep B and Hep C
• C. Hep C and HIV
• D. Hep B and HIV

Answer: (D)

Vaccines exist for Hepatitis A and Hepatitis B, but there is currently no licensed vaccine for Hepatitis C or for HIV. The reason is that Hepatitis C and HIV present unique challenges: Hepatitis C has extraordinary genetic variation and can evade immune responses, making it hard to develop a vaccine that provides durable protection. HIV mutates rapidly and hides in latent reservoirs, which complicates creating an effective vaccine. Because of these challenges, Hepatitis C and HIV are the diseases without vaccines at this time. In practice, prevention relies on standard precautions and post-exposure management, while vaccines are available for Hep A and Hep B.