It is common knowledge in the horse business that horses are susceptible to tetanus. For this reason, it is recommended all horses get vaccinated for tetanus every year. However, many folks do not realize there are two different types of tetanus shots. The yearly tetanus vaccine is a tetanus toxoid and is effective at preventing the disease. However, this vaccine is a toxoid and so it is not effective until 2 weeks after the vaccine is given.
So what do you do if in the interim your horse steps on a nail or develops a laceration and is not vaccinated? Well, there is another product called a tetanus antitoxin and this antitoxin starts working immediately but only lasts about 10 days. However, there are some problems with tetanus antitoxin; it has been reported, although rarely, to cause a serious disease called serum sickness. Many years ago it was recommended that all newborn foals receive tetanus antitoxin immediately after birth. However, because of this potential problem, the use of tetanus antitoxin in newborn foals is not recommended and it is recommended to vaccinate the mare 6 weeks before foaling with the tetanus toxoid, which protects the foal. The second concern about tetanus antitoxin is from new research in Belgium showing that tetanus antitoxin is not 100% effective in preventing the disease. The researchers examined all the tetanus cases over several years at their hospital and found many of them received tetanus antitoxin and yet still developed the disease; tetanus is deadly in the majority of cases. So, make sure your horse is vaccinated every year for tetanus and do not wait until an injury occurs.