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Published on: February 23, 2014
Impact of Universal PCV10 Vaccination on Invasive Pneumococcal Disease in Croatian Children
Iva Butić1,2, Goran Tešović1,3, Kristian Bodulić1
1From the University Hospital for Infectious Diseases, Zagreb, Croatia.
Insights
The introduction of pneumococcal conjugated vaccine 10 (PCV10) significantly reduced invasive pneumococcal disease (IPD) in Croatian children, especially those under five. Current serotypes suggest a need for updated vaccines like PCV15 or PCV20.
Area of Science:
- Pediatric Infectious Diseases
- Vaccinology
- Microbiology
Background:
- Streptococcus pneumoniae remains a leading cause of childhood morbidity and mortality globally.
- Pneumococcal conjugated vaccines (PCVs) are widely used but their impact on disease epidemiology requires ongoing evaluation.
Purpose of the Study:
- To assess the impact of universal PCV10 vaccination on invasive pneumococcal disease (IPD) incidence.
- To analyze changes in serodistribution and antimicrobial resistance of S. pneumoniae strains post-PCV10 introduction in Croatian children.
Main Methods:
- Analysis of 601 invasive S. pneumoniae isolates from children (0-18 years) in Croatia (2005-2023).
- Serotyping by capsular swelling method and antimicrobial susceptibility testing per EUCAST guidelines.
- Comparison of IPD epidemiology in pre-PCV10 and post-PCV10 vaccination periods.
Main Results:
- A significant reduction in IPD incidence due to PCV10 serotypes was observed, particularly in children under 5 (81.0% reduction).
- Bacteremic pneumonia and serotype 3 became more prevalent in the post-PCV10 era.
- Slower increases in penicillin susceptibility and macrolide resistance were noted post-PCV10.
Conclusions:
- PCV10 introduction substantially altered IPD epidemiology in Croatian children, decreasing PCV10 serotype prevalence.
- The evolving serodistribution indicates a need for next-generation pneumococcal vaccines.
- PCV15 and PCV20 are potential candidates for future immunization strategies based on current serotype prevalence.
Introduction:
Despite the worldwide usage of pneumococcal conjugated vaccines (PCVs), Streptococcus pneumoniae remains a major cause of morbidity and mortality among children. This study evaluated the effects of universal PCV10 vaccination on incidence, serodistribution and antimicrobial resistance among S. pneumoniae strains causing invasive pneumococcal disease (IPD) in Croatian children.
Methods:
The study analyzed consecutive, nonredundant invasive S. pneumoniae isolates obtained from children up to 18 years of age, collected through a network of microbiologic laboratories in Croatia from 2005 to 2023. Serotyping was performed by the capsular swelling method. In vitro susceptibility testing was performed according to the EUCAST guidelines.
Results:
During the 19-year study period, 601 invasive S. pneumoniae strains were analyzed. This included 543 isolates in the pre-PCV10 period and 58 isolates in the post-PCV10 period. Bacteremic pneumonia and serotype 3 were significantly more common in the post-PCV10 period. A significant reduction in the incidence of IPD caused by PCV10 serotypes was observed in the post-PCV10 period in all age groups, with the highest reduction of 81.0% in children <5 years. The cumulative incidence of isolates susceptible, increased exposure to penicillin and isolates resistant to macrolides increased significantly slower in the post-PCV10 period.
Conclusions:
The introduction of PCV10 significantly changed the IPD epidemiology in Croatian children. The prevalence of PCV10 isolates decreased, with the current serodistribution suggesting the need for novel pneumococcal conjugates. Given the relatively low prevalence of isolates with PCV10 and PCV13 serotypes, PCV15 and PCV20 may be the most suitable candidates for future use.
