Tetanus is an anaerobic bacterium that grows and multiplies easily under anaerobic conditions or in deep wounds with aerobic infection (aerobic bacteria consume oxygen so that anaerobic bacteria can multiply easily). Due to the growth characteristics and special environmental requirements of tetanus bacillus, tetanus bacillus is more common in soil and rust, this is in line with common sense, but it should be noted that not only rust and soil have tetanus bacillus. Clinically, a tetanus shot should be considered for deeper contaminated wounds, especially those contaminated with clay or lacerated by rust-like iron. Generally, only scratched epidermis, or wounds that are not deep and relatively clean, can be done without tetanus shot as long as proper debridement is done. The tetanus shot is often referred to as protection obtained through passive immunity. Passive immunity is a way to obtain protective antibodies by injecting anti-tetanus globulin after facing a possible infection, and two agents are commonly used: 1. tetanus antitoxin (TAT, from horses) 2, human tetanus immunoglobulin (TIG, derived from human) The former requires skin testing and costs more than ten dollars, while the latter does not require skin testing and is slightly more expensive. There is another kind of protection through active immunity, active immunity means that through the injection of tetanus toxoid, inducing the body to produce its own antibodies to obtain protection. Here to correct a misunderstanding, the medical tetanus vaccine refers to tetanus toxoid preparations, which are toxoid rather than antitoxin. The above mentioned TAT and TIG are sometimes called tetanus vaccine is a common sense misunderstanding, they are therapeutic biological products, not vaccines. The word “tetanus” in the term pediatric tetanus vaccine is used to refer to tetanus toxoid. Active immunity is obtained through a series of vaccination injections, and its acquisition method and effective protection period is clinically complex, plus many people do not strictly complete this procedure, or can not be confirmed, so the clinical trauma by possible infection still take passive immunity. Tetanus needle skin test allergy clinically mainly refers to tetanus antitoxin (TAT, from horse) skin test allergy, can be replaced by injection of human tetanus immunoglobulin (TIG, from human) to obtain protection. If TIG is not available, TAT desensitization injections may be given, in consultation with the health care provider at the consultation. If there is a history of strict vaccination, consult with the visiting physician according to your condition, and you do not necessarily need a tetanus shot if you are within the protection period. How long is the best time to get a tetanus shot after an injury? How long does it protect the body? What should I be aware of if I am pregnant? TAT and TIG are of course the best to be injected as soon as possible after the injury, usually not more than 24 hours, but after that there is still value in injecting (because although tetanus can develop within 24 hours, but the incubation period can be a week or more). Beyond this time, the risk of infection is high and another injection is required. The protection time of active immunity obtained by tetanus vaccination is relatively complicated and can be consulted with the doctor. Those who have been vaccinated for more than 3 years should receive one additional injection of tetanus toxoid. For severely contaminated wounds, in addition to tetanus toxoid injection, TAT or TIG may be injected at another site as appropriate. according to the standard procedure for tetanus control, if a person with no history of immunization is faced with possible infection, tetanus toxoid should be injected to obtain active immunity after TAT or TIG is injected to obtain protection, if the situation permits. However, such measures are not taken clinically for reasons limited to individuals, hospitals and lack of vaccines, and TAT or TIG injections alone are still the mainstay. For pregnant women, the toxicological effects of TAT or TIG are unknown, and caution is needed. However, tetanus toxoid (i.e., tetanus vaccine) is safe and is generally used in the same way as in the general population. For the prevention of neonatal tetanus, if a pregnant woman has received tetanus toxoid in the past, just one injection of tetanus toxoid in early pregnancy, at the latest 3 weeks before delivery, the antibody can pass through the placenta so that the fetus also obtains this protective antibody, and if the pregnant woman has not received tetanus toxoid in the past, another injection should be given 4 weeks after the first injection as a booster.