List any two emergent circumstences when a medical doctor would recommend injection of a preformed antibody into the body of a patient and why?

1.If a person is infected with some deadly microbes, a quick immune is required; as in tetanus, we need to directly inject the preformed antibodies or antitoxin.
2…Even in case of snake bites, the injection given to the patients contains preformed antibodies against the snake venom.
This type of immunization is called passive immunization.