Vaccination against the hepatitis A virus is unnecessary if you:

• A. are over 65 years old
• B. have a family history of hepatitis B
• C. have already had a confirmed hepatitis A infection
• D. have received the influenza vaccine

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the purpose of vaccination, which is to provide immunity against a specific pathogen by stimulating the immune system without causing the disease.
2. Step 2: Recognize that vaccination against hepatitis A is generally recommended for individuals who have not been previously infected or exposed to the virus, as they lack natural immunity.
3. Step 3: Identify that if a person has already had a confirmed hepatitis A infection, their immune system has developed natural immunity, making vaccination unnecessary for them.
4. Step 4: Note that factors such as age over 65, family history of hepatitis B, or having received the influenza vaccine do not provide immunity against hepatitis A and therefore do not eliminate the need for hepatitis A vaccination.
5. Step 5: Conclude that the correct reason for not needing hepatitis A vaccination is having a confirmed past infection with hepatitis A, as this confers immunity.