What is passive immunity?

Passive immunity refers to the immunity acquired through the transfer of antibodies from another individual or source. This type of immunity is temporary, as it does not involve the recipient's immune system actively producing antibodies. Instead, the antibodies received are pre-formed and can offer immediate protection against infections.

For example, a newborn baby receives passive immunity from its mother through the placenta during pregnancy and through breast milk after birth. This provides the infant with a certain level of protection against pathogens the mother has immunity against.

In contrast, immunity gained through vaccination involves the body actively responding to a vaccine by creating its own antibodies—this is referred to as active immunity. A balanced diet and physical exercise contribute to overall health and a functioning immune system but do not directly confer immunity in the way that passive immunity does. Therefore, the correct understanding of passive immunity emphasizes the transfer of antibodies from another source as its foundational characteristic.