Potential impact of pneumococcal vaccination in Denmark

Abstract number: 1732_231

Harboe Z.B., Valentiner-Branth P., Hjuler T., Christensen J.J., Lambertsen L., Mølbak K., Konradsen H.B.

Background: Since 2000, the pneumococcal 7-valent protein-conjugate vaccine (PCV-7) has been implemented in the childhood vaccination programme in several countries. In Denmark (DK), the PCV-7 is only recommended for children in high-risk groups.

Objective: To describe incidence and antibiotic resistance of invasive pneumococcal disease (IPD) and estimate the direct and indirect effect of PCV introduction in DK.

Methods: Review of demographic and laboratory data from IPD cases between 2000 and 2005. Data on pneumococcal meningitis were obtained from the Notifiable Infectious Disease Register. Considering the local serotype distribution, the direct effect of PCV-7, -10, and -13 was estimated in children under 5 years (<5 y), assuming a 90% vaccination coverage and a 97% effectiveness in reducing IPD caused by vaccine-serotypes. Herd immunity effect was estimated assuming a 40% reduction of IPD caused by vaccine-serotypes.

Results: (1) Incidence: The total incidence remained stable throughout the period, ~20/100,000 population, whereas the incidence in <5 y increased from 25 to 34. The highest incidence was observed among adults >65 years, ~69 per 100,000. 92% of cases presented as bacteraemia. Approx. 100 cases of pneumococcal meningitis were registered annually, with an overall mortality of 20%. (2) Vaccine effectiveness: The overall serotype coverage among IPD < 5 y was estimated as: 64% (PCV-7), 82% (PCV-10), and 91% (PCV-13). With an annual average of 86 cases of IPD < 5 y the number of vaccine-preventable cases would be: 48 (PCV-7), 61 (PCV-10) and 68 (PCV-13). The annual number of IPD > 5 y protected by herd immunity would be: 144 (PCV-7), 237 (PCV-10) and 277 (PCV-13). In terms of mortality, 2.1 children <5 y die annually. Introduction of PCV would prevent 1.2 deaths (PCV-7), 1.5 (PCV-10) and 1.7 (PCV-13). The annual number of deaths among IPD > 5 y is 199; 30 fatal cases would be prevented by PCV-7, 46 by PCV-10 and 55 by PCV-13. (3) Antibiotic resistance: 2.5% of the isolates tested for penicillin susceptibility had MIC > 0.125 ug/mL, none had MIC > 2 ug/mL. 5% of isolates presented erythromycin MIC > 1.5 ug/mL.

Conclusions: The incidence of IPD < 5 y increased during 2000–2005 in DK. The PCV-10 and -13 would provide higher protection than PCV-7 based on the serotype distribution, mainly due to presence of serotype 1. Monitoring serotypes, resistance, and mortality related to IPD is essential in order to evaluate the effect of vaccine introduction.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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