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| PERTUSSIS |
Disease
Pertussis (whooping cough) is a highly contagious acute bacterial disease involving the respiratory tract and caused by Bordetella pertussis. It is transmitted by direct contact with airborne discharges from the respiratory mucous membranes of infected persons. It causes a severe cough of several weeks’ duration with a characteristic whoop, often with cyanosis and vomiting. In young infants, the cough may be absent and disease may manifest with spells of apnoea. Although pertussis can occur at any age, most serious cases and fatalities are observed in early infancy and mainly in developing countries. Major complications include pneumonia, encephalitis and malnutrition (due to repeated vomiting). Vaccine is the most rational approach to pertussis control.
Occurrence
Recent estimates from WHO suggest that about 17.6 million cases of pertussis
occurred worldwide in 2003, 90% of which were in developing countries, and that
some 279 000 patients died from this disease.
Risk for travellers
Unprotected infants are at high risk, but all children and young adults are at risk
if they are not fully immunized. Exposure to pertussis is greater in developing
countries.
Vaccine
In contrast to diphtheria and tetanus vaccines which are toxoid, pertussis vaccine is derived from inactivated bacteria. Whole cell pertussis vaccine (wP) is suspension of killed B pertussis inactivated by formalin. Whole cell pertussis became unpopular due to various adverse events though unauthenticated. Thereafter attempts of developing acellular pertussis vaccine (aP) were initiated. In past decade significant progress has been made in the development of pertussis vaccine. As compared to whole cell pertussis vaccine, the cellular pertussis vaccine is acellular associated with less significant reactions.
Pertussis vaccine is usually given as a combination preparation containing other vaccines like tetanus and/or diphtheria. For the routine immunization of infants, primary immunization with pertussis (whooping cough) vaccine is recommended in the form of 3 doses (separated by 1 month intervals) of diphtheria, tetanus, pertussis.
A booster dose should be given 3 years after the primary course.
All travellers should be up to date with the vaccine. Both whole-cell (wP) and acellular (aP) pertussis vaccines provide excellent protection. |
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