Vaccination against the hepatitis A virus is unnecessary if you:

• A. Have a weak immune system.
• B. Are older than 35 years of age.
• C. Have been infected with hepatitis in the past.
• D. Have received a hepatitis B vaccination.

Answer: (C)

The key idea is that immunity after a natural hepatitis A infection is usually lifelong. If you’ve been infected with hepatitis A in the past, your body has built antibodies that recognize and fight the virus, so you’re already protected against reinfection. In that situation, the hepatitis A vaccine wouldn’t add meaningful protection, making vaccination unnecessary.

The other scenarios don’t guarantee immunity or remove the need for vaccination. A weak immune system doesn’t automatically make vaccination unnecessary and in many cases vaccination is still considered safe and beneficial. Being older doesn’t confer immunity to hepatitis A. Having hepatitis B vaccination protects against hepatitis B, not hepatitis A, so it doesn’t affect HAV vaccine needs.