CAUSES OF PERTUSSIS INCIDENCE INCREASE

Bordetella pertussis is an etiological factor of whooping cough. Despite global vaccination programs, this disease remains endemic in many countries and is still recognized as a significant public health problem. It is estimated that in 2014, around 24 million people worldwide contracted pertussis, of whom 160,700 children under the age of 5 died. Two types of pertussis vaccines are available: suspensions based on whole, killed, B. pertussis cells and acellular pertussis vaccines containing highly purified bacterial antigens. Due to concerns of potential neurological side effects of the whole-cell vaccines, less reactogenic acellular vaccines are now more commonly used. In recent years, many developed countries have reported a resurgence of pertussis disease despite of the high vaccine coverage. Several causes have been suggested for the re-emergence of pertussis including waning immunity and bacterial adaptation resulting from the selection pressure of the used vaccinations.