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Epidemiological analysis of pneumococcal serotype 19A in healthy children following PCV7 vaccination

A Tóthpál1, K Laub1, S Kardos1

  • 1Institute of Medical Microbiology,Semmelweis University,Budapest,Hungary.

Epidemiology and Infection
|November 10, 2015
PubMed

Insights

Pneumococcal conjugate vaccines (PCV) led to a rise in disease-causing serotype 19A in Hungarian children. This highly resistant strain dominated in areas with high PCV use, despite stable overall carriage rates.

Area of Science:

  • Microbiology
  • Epidemiology
  • Vaccinology

Background:

  • Global shifts in pneumococcal serotypes followed conjugate vaccine introduction.
  • Serotype 19A emerged as a significant concern due to its invasive potential and antibiotic resistance.

Purpose of the Study:

  • To investigate the prevalence of Streptococcus pneumoniae serotype 19A in Hungarian children.
  • To analyze serotype distribution changes in relation to pneumococcal conjugate vaccine (PCV) uptake.

Main Methods:

  • Screening of 2262 children aged 3-6 years for pneumococcal carriage via nasal swabs.
  • Categorization of children into low and high PCV vaccination rate groups.
  • Analysis of serotype distribution, antibiotic resistance (macrolides, penicillin), and genotyping of 19A isolates.

Main Results:

  • Overall pneumococcal carriage rate remained stable (32.9%) across groups and time.
  • Serotype 19A prevalence increased more than eightfold in the high PCV uptake group.
  • Nearly all 19A isolates exhibited high-level macrolide resistance and elevated penicillin minimum inhibitory concentrations.
  • Genotyping indicated that the dominant 19A strains were distinct from the previous Hungary19A-6 PMEN clone.

Conclusions:

  • PCV widespread use in Hungary correlated with a significant increase in serotype 19A prevalence.
  • The emerging 19A strains possess concerning antibiotic resistance profiles.
  • Serotype 19A became the dominant strain in high PCV uptake areas, highlighting a serotype replacement phenomenon.

Keywords:
Pneumococcusresistanceserotypesvaccination

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