Permanent. Involves memory cells with antibodies to prevent future infection. May be gained through exposure / vaccination..

Acquired immunity

Explanation:  

Acquired immunity is a type of immunity that we obtain by exposing ourselves to new antigens. When our body is exposed to a new antigen, the T cells, and the B cells, which are lymphocytes, attack the antigen by creating specific antibodies and activating other cells that prevent the antigen from harming the body. Some of these B and T cells transform into memory cells that will circulate through our body for years. As a result, when our body is exposed again to the same antigen, the memory cells recognize it and start a quick immune response by synthesizing specific antibodies.

Vaccines use this method. They have a modified or artificial pathogen similar to the real one, so when we are injected with it, our body develops antibodies for that specific pathogen. As a result, if we are infected with the pathogen again, our body will have a quick immune response and stop the infection.