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| DIPTHERIA |
Disease
Diphtheria is a bacterial disease caused by Corynebacterium diphtheriae. The infection commonly affects the throat and may lead to obstruction of the airways and death. Exotoxin-induced damage occurs to organs such as the heart. Nasal diphtheria may be mild, and chronic carriage of the organism frequently occurs; asymptomatic infections are common. Transmission is from person to person, through droplets and close physical contact, and is increased in overcrowded and poor socioeconomic conditions. A cutaneous form of diphtheria is common in tropical countries and may be important in transmission of the infection.
Occurrence
Diphtheria is found worldwide, although it is not common in countries where long-standing routine use of diphtheria vaccine exists.
Risk for travellers
Potentially life-threatening illness and severe, lifelong complications are possible in incompletely immunized individuals. Diphtheria is more frequent in parts of the world where vaccination levels are low.
Vaccine
Diptheria vaccines are prepared from the toxin of Corynebacterium diphtheriae and adsorption on aluminum hydroxide or aluminum phosphate improves anti-genicity. The vaccine stimulates the production of the protective antitoxin. Single-antigen diphtheria vaccine is not available and adsorbed diphtheria vaccine is given as a combination product containing other vaccines.
For primary immunization of children aged between 2 months and 10 years vaccination is recommended usually in the form of 3 doses (separated by 1-month intervals) of diphtheria, tetanus, pertussis (whole or acellular component). In unimmunised individual aged over 10 years the primary course comprises of 3 doses of adsorbed diphtheria [low dose], tetanus.
A booster dose should be given 3 years after the primary course (this interval can be reduced to a minimum of 1 year if the primary course was delayed). Children under 10 years should receive either adsorbed diphtheria, tetanus, pertussis vaccine or adsorbed diphtheria [low dose], tetanus, pertussis vaccine. Individuals aged over 10 years should receive adsorbed diphtheria [low dose] and tetanus vaccine.
A second booster dose of adsorbed diphtheria [low dose] and tetanus vaccine should be given 10 years after the previous booster dose (this interval can be reduced to a minimum of 5 years if previous doses were delayed).
Those intending to travel to areas with a risk of diphtheria infection is high should be fully immunized. If more than 10 years have lapsed since completion of immunization schedule, a dose of adsorbed diphtheria [low dose] and tetanus should be administered.
Staff in contact with diphtheria patients or with potentially pathogenic clinical specimens or working directly with C. diphtheriae or C.ulcerans should receive a booster dose if fully immunized (with 5 doses of diphtheria-containing vaccine given at appropriate intervals); further dose should be given at 10 yrs interval if risk persists. Individuals at risk who are not fully immunized should complete the primary course, a booster dose should be given after 5 years and then at 10 year interval. Adsorbed diphtheria [low dose] and tetanus is used for this purpose; immunity should be checked by antibody testing at least 3 months after completion of immunization.
Diphtheria Antitoxin
Diphtheria Antitoxin is used for passive immunization. It is derived from horse serum and reactions are common after administration; resuscitation facilities should be available by the bed side of the patient before it’s administration.
It is now only used in suspected cases of diphtheria (without waiting for bacteriological confirmation); tests for hypersensitivity should be first carried out.
It is no longer used for prophylaxis. |
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