[Invasive pneumococcal disease in the Community of Valencia. Six years of surveillance (2007-2012)]

Abstract

Introduction: The introduction of conjugated anti-pneumonia vaccines has led to a change in the epidemiology of Invasive Pneumococcal Disease (IPD). The aim of this study is to describe the trends in IPD in the Community of Valencia during the period 2007-2012.

Material and methods: A retrospective, descriptive and longitudinal study was conducted on IPD in the Community of Valencia during the period 2007-2012, The information sources used were the Epidemiological Surveillance Analysis (Análisis de la Vigilancia Epidemiológica (AVE)) and the Valencian Microbiology Network (Red Microbiológica Valenciana (RedMIVA)) of the Valencia Health Department.

Results: The incidence of IPD decreased between 2007 and 2012 in all age groups, mainly in the under 5 year-olds, dropping from 30.5 cases to 12.3 cases per 10(5) inhabitants (p< .001). Pneumonia was the principal presentation of the disease, with a decrease in its rates from 6.9 to 4.1 cases per 10(5) inhabitants (p< .001). A gradual, non-significant, reduction from 26% to 12% (p=.23) was observed in the proportion of cases due to the serotypes contained in the heptavalent vaccine (PCV7), mainly in the under 5 year-olds. The cases due to additional serotypes in 13-valent conjugated vaccine (1, 3, 5, 6A, 7F and 19A) also showed a decreasing trend, mainly in vaccinated under 5 year-olds (52.6% vs 14.3%; p=.03), while the cases due to non-vaccine serotypes significantly increased from 42.3% to 56.7% in the general population (p=.002), and from 47.4% to 78.6% in vaccinated under 5 year-olds (p=.08).

Conclusions: The results of this study show a reduction in the incidence of IPD, with a decrease in the proportion of cases produced by vaccine serotypes, and an increase in the proportion of those not vaccinated. Epidemiological Surveillance is necessary to monitor the trends in the disease.

Keywords: Enfermedad neumocócica invasiva; Incidence; Incidencia; Invasive pneumococcal disease; Pneumococcal conjugate vaccine; Reemplazo de serotipos; Serotype replacement; Vacuna conjugada antineumocócica.