Studie: Mehr Pneumokokken-Fälle nach Einführung der Impfung in Spanien
(ir) Forscher der Uniklinik Barcelona verglichen die Häufigkeit von invasiven (durch Ansteckung verursachten) Pneumokokkenerkrankungen vor und nach der Einführung des 7-valenten Pneumokokkenimpfstoffs Prevenar. Ergebnis: Eine enorme Zunahme der Erkrankungen seit der Einführung des Impfstoffs. Der Anstieg betrug bei unter 2-Jährigen 58% und bei 2- bis 4-Jährigen 135%. Bei Kindern unter 5 Jahren waren die durch Pneumokokken verursachten klinischen Pneumonien und/oder Empyeme (Eiteransammlungen) sogar um 320% häufiger. Der Anstieg werde, so die Studienautoren, vor allem durch verschiedene im Impfstoff nicht enthaltene Sub-Typen (1, 6A, 5, 19A) verursacht.
Emergence of invasive pneumococcal disease caused by nonvaccine serotypes in the era of 7-valent conjugate vaccine
Munoz-Almagro C, Jordan I, Gene A, Latorre C, Garcia-Garcia JJ, Pallares R:
Department of Microbiology, Hospital Universitari Sant Joan de Deu, Esplugues, Spain
BACKGROUND: Little is known about the epidemiology of invasive pneumococcal disease (IPD) after the introduction of 7-valent pneumococcal conjugate vaccine (PCV7) in Spain and other European countries.
METHODS: We performed a 10-year prospective study including all children with culture-proven IPD admitted to Sant Joan de Deu Hospital, a children's center in the southern area of Barcelona, Catalonia, Spain. PCV7 was introduced in June 2001, and the current estimate of PCV7 coverage is 45%-50%.
RESULTS: Comparing the prevaccine period (1997-2001) with the vaccine period (2002-2006), among children aged <2 years, the rate of IPD increased from 32.4 episodes per 100,000 population to 51.3 episodes per 100,000 population (an increase of 58%; 95% confidence interval, 2%-145%), and among children aged 2-4 years, the rate increased from 11.3 episodes per 100,000 population to 26.5 episodes per 100,000 population (an increase of 135%; 95% confidence interval, 31%-320%). At clinical presentation, the rate of pneumonia and/or empyema among children aged <5 years increased from 3.6 episodes per 100,000 population to 15.1 episodes per 100,000 population (an increase of 320%; 95% confidence interval, 98%-790%).
These increased rates of IPD were caused by non-PCV7 serotypes, which represented 38% and 72% of infecting serotypes in the prevaccine and vaccine periods, respectively (P=.001). Penicillin resistance decreased from 48% in the prevaccine period to 27% in the vaccine period (P=.005). In the vaccine period, there was an emergence of previously established virulent clones of non-PCV7 serotypes 1 and 5. There was also an increase in the prevalence of serotypes 19A and 6A expressed with different clonal types, including Spain(23F)-1 and Spain(6B)-2.
CONCLUSIONS: Since the introduction of PCV7 for children, there has been an emergence of IPD caused by virulent clones of non-PCV7 serotypes that has been associated with significant clinical changes and a decrease in antibiotic resistance. - Clin Infect Dis. 2008 Jan 15;46(2):174-82
