Are there vaccines for protozoal infections?

• A. YES
• B. SOMETIMES
• C. UNKNOWN
• D. NO

Answer: (D)

Protozoal infections pose a tough vaccine target because these parasites have complex life cycles with multiple forms that can change their surface proteins. A vaccine would need to trigger protective immunity against several stages and variants, which is very hard to achieve consistently in humans. As a result, there are no widely used vaccines that provide broad, long-lasting protection against protozoal diseases. There has been progress with malaria vaccination (a vaccine named Mosquirix), which offers partial protection in certain settings, but it does not fully prevent infection and isn’t a universal solution. Because of these challenges, the general answer is that there are no vaccines for protozoal infections.