RESUMO
INTRODUCTION: An increase in whooping cough in most of the developed countries has been detected in the last decade. OBJECTIVE: To determine whether the administration of dTpa vaccine instead of DTPa fifth dose is contributing to the appearance of these cases. METHODS: A descriptive study based on cases of whooping cough reported during an epidemic period in the city of Alicante in the first 5 months of 2014. Only pertussis cases confirmed by PCR were included in the study, and only those vaccinated with 5 doses were included in the analysis of the period of protection. RESULTS: A total of 104 cases of pertussis confirmed by PCR were reported, with 85 cases (82%) having had 5 doses of vaccine. The mean time and standard deviation (SD) of protection was 2.1±1.1 years with dTpa, and 5.1±1.5 years with DTPa (p<.001). In the protection, adjusted for age, it was observed that, after 3 years, only 47.6% of people vaccinated with dTpa were still protected, while people vaccinated with DTPa were 100% protected (P<.001). CONCLUSIONS: This study found that people who were properly vaccinated against pertussis and received their last re-vaccination dose with dTpa had a shorter period of protection than those who were vaccinated with DTPa.