In short
Tetanus toxoid adsorbed on aluminium phosphate is an inactivated bacterial toxin used in vaccines to prevent tetanus, a serious and often fatal disease caused by Clostridium tetani. It is also studied as part of combination vaccines, including one Phase 3 trial in 240 pregnant women and their infants focused on immunity to whooping cough. The toxoid is already authorised in several combination vaccine products.
Key points
- Tetanus toxoid is a detoxified form of the tetanus toxin used in vaccines.
- A Phase 3 trial (NCT05856396) studied a combination vaccine containing tetanus toxoid in 240 pregnant women and their infants.
- The trial measured antibody responses to pertussis vaccination in infants born to vaccinated mothers.
- The trial status is Completed.
- Tetanus toxoid is used in combination vaccines alongside diphtheria, pertussis, hepatitis B, polio, and Haemophilus type b components.
- A protective level of tetanus antitoxin is considered to be 0.01 IU/ml in serum.
What is tetanus toxoid?
Tetanus toxoid adsorbed on aluminium phosphate is a vaccine component derived from the tetanus toxin. The toxin is produced by Clostridium tetani and is detoxified with formaldehyde before being purified and adsorbed onto aluminium phosphate. Each 0.5 ml dose of a tetanus and diphtheria toxoid vaccine contains 2 Lf of tetanus toxoid and 2 Lf of diphtheria toxoid, along with an aluminium adjuvant. Tetanus toxoid is not given as a standalone product in most settings; it is available as part of combined vaccines.
How does tetanus toxoid work?
Tetanus is caused by an extremely potent neurotoxin produced by Clostridium tetani. Protection against the disease depends on the development of neutralising antibodies to this toxin. When tetanus toxoid is injected, the immune system recognises the inactivated toxin and produces antibodies against it. A serum tetanus antitoxin level of 0.01 IU/ml, measured by a neutralisation assay, is considered the minimum protective level. In a study of adults with very low pre-immunisation antitoxin levels, 70% achieved protective levels after two doses, and all 16 adults tested achieved protective levels after three doses.
Which conditions is tetanus toxoid used or studied for?
- Tetanus (lockjaw) — a serious, often fatal disease caused by a neurotoxin from Clostridium tetani. Tetanus toxoid is used to prevent this disease.
- Whooping cough (pertussis) — tetanus toxoid is included in combination vaccines studied for maternal immunisation to protect infants against pertussis.
- Diphtheria — tetanus toxoid is combined with diphtheria toxoid in a vaccine that protects against both diseases.
How is tetanus toxoid given?
Tetanus toxoid is given by intramuscular injection as part of combination vaccines. The vaccine containing tetanus and diphtheria toxoids appears as a homogenous milky white suspension after shaking. In the Phase 3 trial, the combination vaccine Vaxelis containing tetanus toxoid was given as a 0.5 ml intramuscular injection. Tetanus vaccines are available as combined vaccines rather than as a standalone product.
What do the clinical trials show?
One Phase 3 trial (NCT05856396) studied tetanus toxoid as part of the Vaxelis combination vaccine in 240 pregnant women and their infants. The trial, titled "Maternal determinants of infant immunity to pertussis (MADI-02)", was interventional and has been completed. The main objective was to identify determinants of antibody-mediated immunity to pertussis in infants born to mothers immunised during pregnancy. Specifically, the trial aimed to identify predictors of vaccine responses in pregnant women, the transfer of maternal antibodies to the newborn, and vaccine responses in infants.
What is the trial measuring?
The primary outcome measured in this trial is the magnitude of the antibody responses to pertussis vaccination. The trial also examined how maternal antibodies are transferred to the newborn and how infants respond to vaccination after birth.
What side effects are known?
The supplementary sources provided do not include detailed side effect information for tetanus toxoid. The vaccine contains residual formaldehyde (less than 100 mcg per dose) and a trace amount of thimerosal from the manufacturing process. No side effect data from the clinical trial or other provided sources is available for this page.