[Situation of pertussis in Valencian Community: an epidemic revival?].

Introduction: Pertussis is a highly contagious vaccine-preventable disease. An increasing incidence has been reported in several countries around the world in the last few years. The aim of this study is to analyze the situation of pertussis in the Valencian Community (Spain), with the purpose of verifying the increased incidence of the illness.

Methods: A descriptive analysis of probable and confirmed cases detected during 2011 was conducted. Methods used for Bordetella pertussis detection from clinical samples were: culture isolation, polymerase chain reaction (PCR)-based detection of bacterial DNA, and/or detection of specific IgM antibodies. The disease incidence and other epidemiological variables were estimated. These results were compared to data collected in previous years (2008-2010). The Epidemiological Surveillance Analysis and Microbiological Surveillance Network integrated systems of the regional Department of Health were used as sources of information.

Results: In 2011, 249 cases of pertussis were detected (incidence rate of 4.89×10(5) inhabitants). This rate is statistically significantly higher than those reported in 2008 (0.73×10(5) inhabitants), 2009 (0.53×10(5) inhabitants), and 2010 (0.53×10(5) inhabitants). The highest incidence rate was observed in cases younger than one year old (252.97×10(5) inhabitants), with marked differences compared to the rest of age groups. More than two-thirds (69%) of reported cases were confirmed by a laboratory test. Detection of specific serum IgM antibodies was positive in 10% of cases, culture isolation was positive in 17%, and PCR-based detection of bacterial DNA in 35% of cases.

Conclusions: The results of this study show a clear increase of pertussis incidence in the Valencian Community during 2011.