For which of the following conditions is a prophylactic vaccine currently unavailable?
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Answer: C. HCV
Explanation
Hepatitis C virus exhibits extremely high mutation rates within its envelope glycoproteins. This rapid genetic variability allows the virus to evade host immune surveillance easily. Consequently, a safe and effective prophylactic vaccine is currently unavailable for HCV. HCV is a bloodborne pathogen that causes chronic liver inflammation, fibrosis, and cirrhosis. Prophylactic vaccines stimulate the immune system to prevent initial viral infections. Developing vaccines requires stable viral antigens that do not mutate unpredictably.
Public health organizations rely on screening blood supplies to prevent hepatitis C transmission. Direct-acting antiviral medications can cure HCV infections despite the lack of a vaccine. Researchers continue studying viral mechanisms to overcome the challenges of vaccine design. HAV is preventable using safe and effective prophylactic vaccines widely administered today. HBV has a successful prophylactic vaccine that protects millions against chronic infection. HEV has approved vaccines available in certain regions to prevent waterborne outbreaks.
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