663. Impact of Infant Pneumococcal Vaccination on The Epidemiology of Invasive Pneumococcal Disease in Belgium, 2002-2010
Session: Poster Abstract Session: Pneumococcal Vaccines
Friday, October 21, 2011
Room: Poster Hall B1
  • Poster IDSA 2011 1.pdf (456.2 kB)
  • Background:  In Belgium, the seven valent pneumococcal vaccine (PCV7) was introduced in the national immunization program by 2007. We evaluated the effect of the infant vaccination program on the epidemiology of invasive pneumococcal disease (IPD) in the Belgian population.

    Methods:  Serotyping was performed on 13 998 bacteremic and pleural fluid isolates sent to the Belgian National Reference Laboratory (NRL) between 2002 and 2010. We compared the distribution of serogroups (SGs) between the pre- (2002-2004) and post-PCV7 (2007-2010) era for children (<18 years), adults (18-59 years) and elderly individuals (≥60 years).

    Results:  The yearly number of isolates sent to the NRL increased by 21% post-PCV7. Post-PCV7, IPD cases caused by PCV7-SGs decreased by 63% and non-PCV7-SG cases increased by 137% in subjects ‹ 18 years causing overall IPD cases to remain stable in this age group. Post-PCV7, PCV7-SGs decreased by 21% and 24%  and non-PCV7-SGs increased by 74% and 84% in the 18-59 years and ≥ 60 years age groups, respectively causing an increase of IPD cases in these age groups. The proportion of cases caused by PCV7-SGs in subjects <18 years decreased from 69% pre-PCV7  to 26% post-PCV7 (p <0.005) and the majority of IPD cases caused by PCV7-SGs were caused by SG 19. Post-PCV7, the prevalence of PCV7-SGs decreased from 38.2% to 21.8% and from 56.7% to 35.4% in subjects in the age groups 18-59 and ≥ 60 years, respectively (p <0.005). After PCV7 introduction SGs 1, 7 and 19 showed the largest increase in prevalence among subjects aged <18 years. Subtyping reveals that the increase of SG19 occurred due to the increase of serotype 19A in this age group (p <0.005). After the introduction of infant PCV7 the largest rise in prevalence was noted for SGs 7, 12 and 22 (p <0.005) in the two older age categories. Compared to the pre-PCV7, the overall PCV13 coverage rate decreased from 84.7% to 68.9% (p <0.005) and the coverage rate of the 23-valent pneumococcal polysaccharide vaccine (PPV23) decreased slightly from 96.4% to 93.2% (p <0.005) post-PCV7.

    Conclusion: PCV7 has a great impact on SG distribution of IPD isolates of vaccinated as well as unvaccinated subjects. SG replacement forms a major threat to the success of PCV7. In the future PCV13 might represent an attractive alternative.

    Subject Category: I. Adult and Pediatric Vaccines

    Laurens Liesenborghs, Internal Medicine, University Hospitals Leuven, Leuven, Belgium, Jan Verhaegen, MD, PhD, Microbiology, University Hospitals Leuven, Leuven, Belgium, Willy E Peetermans, MD, PhD, General Internal Medicine and Infectious Diseases, University Hospitals Leuven, Leuven, Belgium and Johan Flamaing, MD, PhD, Geriatric Medicine, University Hospitals Leuven, Leuven, Belgium


    L. Liesenborghs, None

    J. Verhaegen, None

    W. E. Peetermans, None

    J. Flamaing, None

    Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.