The vaccine used in the United States is actually multiple diphtheria and tetanus toxoids combined with acellular pertussis (DTaP).
The risk with DTaP is considerably lower.
The most serious risk of DTaP vaccine is a severe allergic reaction.
For children, vaccination against tetanus is normally included in a vaccine called DTaP that protects against diphtheria, tetanus, and whooping cough (acellular pertussis).
At age 11 or 12, Td vaccine (tetanus and diphtheria) should be given if at least five years have elapsed since the last dose of DTaP.
