Tetanus immunization status
Tetanus is a relatively rare disease caused by G(+) anaerobic sporulating bacteria – Clostridium tetani.
Tetanus prevention at hospital emergency departments in France
Tetanus infections are now rare in France and developed countries, thanks to routine immunization. However since 1994, specific mortality due to tetanus has remained constant at 0.4 per million persons. Several groups within the population remain at elevated risk of insufficient immunization coverage, namely the elderly, women, and immigrants. Moreover, the abolition of obligatory national military service in France and increased immigration are likely to decrease vaccination coverage over the next decades.
In 2000, almost 1,320,000 patients were referred to the 550 French hospital emergency departments for wounds, accounting for 12% of the 11 million referrals.
The prevention of tetanus infection in the emergency departments consists of an appropriate wound cleaning and/or the injection of immunoglobulin and/or vaccine as per guidelines from the French ministry of Health which are complex and often not properly followed.
Tetanus immunity diagnosis today
ELISA is considered by the World Health Organization as the golden standard, with a threshold of 0.1 IU/ml, to diagnose tetanus immunization status. This threshold is 10 times higher than the serum antitoxin level considered to be protective. Unfortunately, with time to result ranging from 48 to 72 hours, ELISA cannot provide rapid enough result for use in emergency departments.
Unless a patient’s medical history can be obtained, immunization status is frequently determined from the immunization history reported by the patient, which is known often to be inaccurate. This results in the following statistics:
The algorithm based on both wound characteristics and patients’ immunization status is difficult to apply. First, the severity of the wound does not accurately predict the risk of tetanus; for example, a small cut while gardening (contact with soil) may entail a greater risk than a larger wound made with a clean kitchen knife. Second, enzyme-linked immunosorbent assay (ELISA) is finally the only methodology available for evaluation of serum tetanus antitoxin levels.
The result is a quasi-systematic and often arbitrary injection of immunoglobulins.
An emerging generation of rapid tests
In the past few years, rapid tests for tetanus have been developed and promoted for hospital use. These are immunochromatographic, or lateral flow membrane-based tests offering a Yes/No-result within 15 minutes after one drop of whole blood is deposited on the strip. For tetanus immunization status, they can provide a rough indication of the patient protection level: antibodies above or below 0.1IU/ml.
The benefit of these tests are as follows:
How Magnisense will improve Tetanus rapid testing
Magnisense can upgrade traditional immunochromatographic tests into high performance quantitative tests based on MIAtek™ magnetic technology. The key features of traditional lateral flow membrane tests are preserved (easy-to-use, rapid), but Magnisense technology will add major features to those:
Tetanus is a relatively rare disease caused by G(+) anaerobic sporulating bacteria – Clostridium tetani.
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The bacterium enters the body through an open wound as a result of contact with contaminated soil, manure or rusted metal. Such cases may occur in open fractures, scalds, ulcerous patients, middle ear infections, abortions, childbirth, intramuscular injections or surgical procedures in | |
| field conditions. There are even cases of tetanus ascribed to the use of toothpicks, acupuncture procedures and body piercing. Although vaccination is administered systemically in developed countries, immunity is not acquired for life. In the USA 70% of the cases and 80% of deaths are noted among people of 50 and more years of age (mostly never vaccinated). The death rate among people of 30 and fewer years of age is close to none. |
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Tetanus prevention at hospital emergency departments in France
Tetanus infections are now rare in France and developed countries, thanks to routine immunization. However since 1994, specific mortality due to tetanus has remained constant at 0.4 per million persons. Several groups within the population remain at elevated risk of insufficient immunization coverage, namely the elderly, women, and immigrants. Moreover, the abolition of obligatory national military service in France and increased immigration are likely to decrease vaccination coverage over the next decades.
In 2000, almost 1,320,000 patients were referred to the 550 French hospital emergency departments for wounds, accounting for 12% of the 11 million referrals.
The prevention of tetanus infection in the emergency departments consists of an appropriate wound cleaning and/or the injection of immunoglobulin and/or vaccine as per guidelines from the French ministry of Health which are complex and often not properly followed.
Tetanus immunity diagnosis today
ELISA is considered by the World Health Organization as the golden standard, with a threshold of 0.1 IU/ml, to diagnose tetanus immunization status. This threshold is 10 times higher than the serum antitoxin level considered to be protective. Unfortunately, with time to result ranging from 48 to 72 hours, ELISA cannot provide rapid enough result for use in emergency departments.
Unless a patient’s medical history can be obtained, immunization status is frequently determined from the immunization history reported by the patient, which is known often to be inaccurate. This results in the following statistics:
- Erroneous anti-tetanus disease prevention in 30 to 40% of cases.
- Downward biases for 5 to 10% of patients, generally most exposed to the risk of tetanus.
- Upward biases in 17 to 30% of cases, especially with tetanus immunoglobulin (mainly of human origin), expensive and being able to convey unknown pathogenic agents (the risk of communicable disease due to the injection of human blood products is small but should nonetheless encourage a responsible attitude to prescription, with diagnostic tests used to determine vaccine status accurately in the emergency department itself).
The algorithm based on both wound characteristics and patients’ immunization status is difficult to apply. First, the severity of the wound does not accurately predict the risk of tetanus; for example, a small cut while gardening (contact with soil) may entail a greater risk than a larger wound made with a clean kitchen knife. Second, enzyme-linked immunosorbent assay (ELISA) is finally the only methodology available for evaluation of serum tetanus antitoxin levels.
The result is a quasi-systematic and often arbitrary injection of immunoglobulins.
An emerging generation of rapid tests
In the past few years, rapid tests for tetanus have been developed and promoted for hospital use. These are immunochromatographic, or lateral flow membrane-based tests offering a Yes/No-result within 15 minutes after one drop of whole blood is deposited on the strip. For tetanus immunization status, they can provide a rough indication of the patient protection level: antibodies above or below 0.1IU/ml.
The benefit of these tests are as follows:
- avoid frequent over-prescription of gammaglobulins,
- mainly of human origin, these injections carry risk of contamination,
- reduce costs to hospitals which seek to limit unnecessary injections,
- avoid under-prescription of tetanus immunoglobulin when the patient is not protected,
- augment the execution of vaccine prescription, based on the objective evaluation of immunization status.
How Magnisense will improve Tetanus rapid testing
Magnisense can upgrade traditional immunochromatographic tests into high performance quantitative tests based on MIAtek™ magnetic technology. The key features of traditional lateral flow membrane tests are preserved (easy-to-use, rapid), but Magnisense technology will add major features to those:
- Quantification of the antitoxins rate, instead of Yes/No answer: the MIAtektor™ will return a quantity of antibodies instead of a simple threshold
- Improved compliance to hospital best practices
- Objective reading, instead of visual, subjective, reading
- No influence of blood haemolysis on the result as it is a magnetic reading, not a colour reading. The result reading can thus be done at any time by the medical doctor in charge.
- Readily archivable results that can be automatically forwarded to the Personal Health Record after validation by the proper Authority: central lab of the hospital, senior MD, etc.
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