Tetanus

Causative agent Clostridium tetani 

Vaccine /  tetanus toxoid is prepared by the detoxification of tetanus toxin which is procured by growing a standard hypertoxigenic strain of C .tetani

The number of LF of toxoid in a single human dose doesnot exceed 25 LF if more than one dose is recommended  for primary immunization .A suitable antimicrobial preservative other than phenol is added if the vaccine is to be filled in multidose container A aluminum as an adjuvant ,does not exceed 1.25 mg and that of calcium 1.3 mg per a single human dose .A preservative other than phenol is added .

Storage

The tetanus adsorbed vaccine is not frozen and remain stable at temperature between 2-8 C .if frozen it not be used for immunization

Immunization schedule tetanus vaccine is recommended for use of 

1-children as apart of immunization schedule for vaccine preventable disease

2-preynant women

3-individual who have suffered injury suspected to be contaminated with C .tetanus

Route of administration tetanus vaccine is routinely injected intramusularly or subcutaneously .The intramuscular route is preferred for adsorbed products .injection are usually in the upper thigh or deltoid .The thigh is often preferred in infants because of the larger muscle mass but for children 18 months and above deltoid can be used .The gluteal region should be usually avoided

Commercial preparations

Tetanus vaccine is available as a single vaccine .however it is most often associated with other vaccines as either double vaccine ,tetanus –diphtheria ,tetanus –polio , tetanus –flu or triple vaccine ,diphtheria –tetanus –polio ,diphtheria tetanus pertussis ,diphtheria –tetanus – typhoid or quadruple vaccine diphtheria –tetanus –pertussis –polio ,or even quintuple diphtheria-tetanus-pertussis –polio –measles

Efficacy of TT

Injection into man of 2-3 doses of toxoid (0.5 ml )each at properly spaced duration raises nthe antitoxin level of blood within a few weeks to protective status .the level of adequate protection has varied from study to study and ranged between 0.005 to 0.1 IU/  ml presently a level of 0.01 IU /   ml of serum is accepted as adequate .the immunity provided by one full course of three injection is long lasting and may persist life long .it has been seen in many studies that circulating antitoxin level after immunization with toxoid falls gradually for 10 years and then remains more or less stationary .

Adverse reactions

Tetanus toxoid is a safe and effective vaccine .purified fluid tetanus toxoid ,prepared with protein –free medium ,is one of the least irritating

Of vaccines .Yet occurrence of adverse effects has been reported in literature .the reactions are

1. local (swelling ,redness and pain up to 10 days after injection_)
2. systemic (pyrexia ,headache ,malaise ,maylgia ,urticaria )

Acute anaphylaxis ,peripheral neuropathy ,elevated IgE levels ,Elevated ant A and Anti B antibodies .

Future prospects

1. Oral vaccine :tetanus vaccine orally after enclosing it in an acid resistant granule to facilitated mass immunization and greater acceptability .A 10-15 times greater dose of toxoid is required to generate immune response if given orally
2. Recombinant DNA vaccine against tetanus

Afragment  of tetanus toxin has been expressed in an insoluble form in E.coli and partially purified .this used in animal mice but not used in man .