Dear Dr Dhrupthob,
Just to add to Dr. Yakubu's thorough response above:
In the case of an injury, if the injury is severe or the patient’s previous tetanus immunization history is unknown, physicians may still give a dose of TTCV (preferably Td). In these cases where a person's vaccination status is incomplete or unreliable, it is recommended that they return to complete the full schedule (as described above), to ensure lifelong protection.
Best,
Stephanie