[Whooping cough in the first year of life in a region with high vaccination coverage].

INTRODUCTION

Despite vaccination, reports of cases and outbreaks of pertussis (whooping cough) continue to appear sporadically, sometimes in young children who are at higher risk of severe disease. The aim of the present study was to evaluate the impact of this infection in infants in a region with high vaccination coverage in the pediatric population.

PATIENTS AND METHODS

We performed a retrospective observational chart-review study of pertussis cases occurring over a decade (1999-2008), microbiologically confirmed through a polymerase chain reaction technique that amplifies the IS481 Bordetella pertussis sequence.

RESULTS

There were 54 confirmed cases, of which 33 (61.1%) occurred in infants aged less than 3 months. Cases were detected in all the study years, with periodic outbreaks (1999, 2004 and 2008). Half of the cases occurred in summer. Due to their young age, 55% of the infants had not received a vaccine dose and only 11% had received the first three doses. Hospitalization was required in 39 cases (72%) and admission to the pediatric intensive care unit in 17 cases (31.5%). One premature infant, with symptoms compatible with malignant pertussis, died at 49 days of life.

CONCLUSIONS

Despite the high pertussis vaccination coverage, infants aged less than 6 months continue to be at risk of severe disease. New preventive strategies are required to further reduce the impact of this infection.