Passive immunity is acquired through which?

• A. Immunity developed after an infection.
• B. Immunity you get through immunization.
• C. Immunity you're born with.
• D. Immunity from antibiotics.

Answer: (B)

Passive immunity is immunity provided by antibodies that come from outside the body rather than being produced by your own immune system. It happens quickly when antibodies are transferred from another source, such as a mother passing antibodies to her fetus across the placenta or through breast milk, or when you receive medical preparations that contain antibodies (immune globulins). This protection is fast but temporary because the antibodies will eventually be broken down and your body hasn’t made its own memory cells to remember the invader.

The other ideas describe active immunity, where your immune system makes its own antibodies after exposure to an infection or after vaccination, leading to longer-lasting protection. Antibiotics, on the other hand, don’t confer immunity at all—they treat bacteria but don’t provide antibody protection.