Patients with prior tetanus immunisation require tetanus toxoid if more than 5 years have elapsed since their last booster.
Contaminated burns wounds in patients who never completed primary vaccination may also require tetanus immunoglobulin.
The recommended use of booster tetanus vaccines and the use of human tetanus immunoglobulin is outlined in the Australian Government, Department of Health & Ageing/NHMRC link below:
http://www.immunise.health.gov.au/internet/immunise/publishing.nsf/Content/Handbook-tetanus