Tetanus

1. Causative Organism
2. Clinical Signs, Symptoms and Complications
3. Method of Transmission
4. Public Health Significance  
5. Prevention - Immunisation
6. Vaccine/s and Vaccination
7. Efficacy and Effectiveness
8. Availability
9. Dosage and Administration
10. Indications and Recommendations
11. Contraindications
12. Adverse Events
13. Risks vs Benefits

Causative Organism

Clostridium tetani, a gram-negative, spore-forming bacilli. The bacteria produce a toxin that acts on the neuromuscular junction to cause tetanus. 

Signs, Symptoms and Complications

• The incubation period varies from 3-21 days, with an average of eight days.
• Tetanus is an acute, often fatal disease. It is characterized by muscular rigidity and very painful muscle contraction spasms.
• When severe, it is associated with a characteristic facial grimace (risus sardonicus) and arching of the back (opisthotonus).
• The patient suffering from tetanus remains alert unless they become severely hypoxic.
• There is no "cure" for tetanus, just supportive treatment and management of complications.
• Tetanus disease does not cause immunity because so little of the potent toxin is required to cause the disease. Persons recovering from tetanus should begin or complete the vaccination series.
  

Baby has neonatal tetanus with complete rigidity. Courtesy of Centers for Disease Control and Prevention

Method of Transmission

• The bacterium spores are very difficult to kill as they are resistant to heat and many chemical agents. C. tetani spores are ubiquitous in the environment but are particularly common in the soil and in the intestines and faeces of many household and farm animals. The bacteria usually enter the human body through a puncture in the skin, which can be trivial and unnoticed.
• Tetanus is not spread from person to person. Many types of injuries can allow tetanus bacilli to enter the body.
• Any wound that may involve contamination with tetanus bacilli should be attended to as soon as possible and appropriate immunisations offered.

Public Health Significance

• Tetanus occurs worldwide and is more frequent in warmer climates and months.
• Neonatal tetanus, from infection of the umbilical stump is common in some countries with developing economies. Where women have been immunised appropriately against tetanus the incidence is reduced.
• Tetanus is the only vaccine-preventable disease that is infectious – but not transmissible human to human.
• In countries with developed economies, tetanus has a 10% case fatality rate despite adequate supportive care.

New Zealand Epidemiology

(From the 2006 New Zealand Immunsiation Handbook, Ministry Of Health)

During 1980–92, 86 cases of tetanus occurred in New Zealand and there were eight deaths, a case fatality rate of 9.3 percent. Of all cases of tetanus, 79 percent were over 40 years of age. Of those who died, seven were over 70 years of age and one was 58 years; seven of the eight were female. The average incidence in New Zealand of 0.20 per 100,000 for the 13-year period compares with a 1992 rate of 0.08 in Australia, 0.01 in Canada, 0.02 in England, 0.04 in Scotland and 0.02 in the United States (US).

From 1993 to 2000 there were 18 cases of tetanus notified to the medical officers of health, a range of zero to six cases a year. Six cases were reported in 1999; two were in the age group 40–49 years and four were over 70 years of age. Four of the cases were unimmunised, and there was no information on the immunisation history of the other two cases. A total of eight cases were notified from 2001 to 2004, and among these was an unimmunised child aged one year diagnosed with tetanus in 2001. The single case notified in 2004 was a female aged 60–65 years with an unknown immunisation history, although there were five cases hospitalised with tetanus. Not all cases of tetanus are notified.

Prevention

Immunisation is the only method of preventing tetanus.

Prevention - Universal Tetanus Immunisation

• Infant tetanus vaccination recommendations aim to develop and maintain tetanus protection through a primary and booster series of vaccines.
• The vaccine is produced from tetanus bacteria that have been cultured to produce toxins that are then detoxified with formaldehyde to produce toxoids. The tetanus toxoid is adsorbed onto aluminium hydroxide.
• All individuals should receive a primary course and two boosters. Further dose recommendations differ – the range is none to 10 yearly to age specific boosters.
• Antibodies are made against the toxin, which prevent it binding to the neuromuscular junction during infection and causing tetanus.
• Individual protection is required against tetanus because there is no person-to-person spread.
  

Prevention and Wound Management

• Any wound can be a source of tetanus infection although a higher risk exists in those contaminated with soil, faeces, or saliva, or with non-viable tissue such as burns of crush injury. 
• All wounds that may be contaminated should be cleaned and debrided.
• In addition to the surgical toilet the use of passive or active immunisation is recommended.
  

Vaccination in Wound Management

• Passive immunisation, given as tetanus immune globulin (TIG), or tetanus antitoxin (250-500 IU IM) and penicillin (1000 U/mL IM) is recommended in conjunction with cleaning and debridement of contaminated wounds.
• In many countries, including New Zealand, additional precaution recommends a specific tetanus booster dose is given for a person presenting with a contaminated wound depending on the previous immunisation history.
  

Efficacy and Effectiveness

• In most studies 100 percent of infants have protective levels of tetanus antibody after three doses of vaccine given at intervals of one month or longer.
• A three dose primary series gives protection for 5-10 years or longer.

Availability

• In New Zealand, the tetanus vaccine is available as a component of a combination vaccine. The diphtheria, tetanus, acellular pertussis, inactivated polio vaccine, hepatitis B and Haemophilus influenza type b. The publicly funded vaccine for the infant series is the combined DTaP-IPV-HepB/Hib vaccine (Infanrix^® -hexa, GSK). A booster is offered at four years of age, prior to starting school of DTaP-IPV (Infanrix™-IPV, GSK).

• An adult dose of diphtheria and tetanus vaccine Td (ADT^®-Booster) is recommended at 45 and 65 years of age. This is also the funded vaccine for wound management. (Immunisation Handbook 2006, Ministry of Health)

Dosage and Administration

• In New Zealand, DTaP-IPV-HepB/Hib (Infanrix^®-Hexa, GSK) is given at six weeks, three months and five months. A booster DTaP-IPV (Infanrix™-IPV, GSK)is given at four years. An adult tetanus diphtheria booster (ADT^®-Booster) is offered at 45 and 65 years of age.

Indications and Recommendations

• Universal primary immunisation: The WHO and the Extended Programme on Immunisation recommend universal immunisation of all children in all countries with a 3-dose primary course of tetanus vaccine given at 4-8 weekly intervals, commencing at 2-4 months of age and completed within the first 6-12 months of life. If necessary, the primary course can be completed at monthly intervals for a catch-up schedule.
• Booster doses should ideally be given prior to entering school (4-5 years) and a later adolescent dose (10-13 years).
• Adult booster recommendations vary by country, from as regularly as 10 yearly (USA) to one final dose 10 years after 4th dose (UK).
• Unimmunised pregnant women - Immunisation is recommended in pregnancy and lactation for previously unimmunised women to reduce the risk of maternal and neonatal tetanus.

 Contraindications

• Previous anaphylactic reaction to a dose of tetanus vaccine or any of its components.
• Patients who develop an encephalopathy within 7 days of receipt of a dose of tetanus vaccination containing a pertussis component should be changed to a monovalent tetanus dose or a combination vaccine not containing a pertussis component. 
• Patients with evolving neurological conditions should be vaccinated with a tetanus vaccine that does not contain a pertussis component.
  

Adverse Events

• Local reactions such as redness or swelling around the injection site can occur and may last for a few days.
• Headache, malaise, myalgia and fever are uncommon.
• Rare serious adverse events include brachial neuritis (0.5-1 per 100,000 doses) and anaphylaxis (1.6 per million doses).
  

Link to NZ 2006 Immunisation Handbook Chapter 5 - Tetanus

Tetanus Immunisation Flowchart Tetanus prone wounds algorithm for tetanus wound injuries.