Molecular Epidemiology of Pneumococcal Colonization in Response to Pneumococcal Conjugate Vaccination in Children with Recurrent Acute Otitis Media

Abstract

A randomized double-blind trial with a 7-valent pneumococcal conjugate vaccine was conducted in The Netherlands among 383 children, aged 1 to 7 years, with a history of recurrent acute otitis media. No effect of vaccination on the pneumococcal colonization rate was found. However, a shift in serotype distribution was clearly observed (R. Veenhoven et al., Lancet 361:2189-2195, 2003). We investigated the molecular epidemiology of 921 pneumococcal isolates retrieved from both the pneumococcal vaccine (PV) and control vaccine (CV) groups during the vaccination study. Within individuals a high turnover rate of pneumococcal restriction fragment end labeling genotypes, which was unaffected by vaccination, was observed. Comparison of the genetic structures before and after completion of the vaccination scheme revealed that, despite a shift in serotypes, there was clustering of 70% of the pneumococcal populations. The remaining isolates (30%) were equally observed in the PV and CV groups. In addition, the degree of genetic clustering was unaffected by vaccination. However, within the population genetic structure, nonvaccine serotype clusters with the serotypes 11, 15, and 23B became predominant over vaccine-type clusters after vaccination. Finally, overall pneumococcal resistance was low (14%), and, albeit not significant, a reduction in pneumococcal resistance as a result of pneumococcal vaccination was observed. Molecular surveillance of colonization in Dutch children shows no effect of pneumococcal conjugate vaccination on the degree of genetic clustering and the genetic structure of the pneumococcal population. However, within the genetic pneumococcal population structure, a clear shift toward nonvaccine serotype clusters was observed.

Streptococcus pneumoniae Surface Protein PcpA Elicits Protection against Lung Infection and Fatal Sepsis

“…It has also been reported that colonization with Staphylococcus aureus of healthy children is inversely correlated with colonization with vaccine-type S. pneumoniae (3,31,44,57). This negative correlation is not seen between S. aureus and non-vaccine-type S. pneumoniae.…”

“…Of even greater concern, however, is the increased incidence of colonization and disease caused by non-vaccine-type pneumococci (3,54,57), which had been predicted by prior studies using mathematical models (29,30). It has been observed that in a Native American population in Alaska, the continued use of the 7-valent vaccine has resulted in almost complete replacement disease caused by vaccine types not present in the 7-valent vaccine (54).…”

Distribution of pilus islands of group B streptococcus associated with maternal colonization and invasive disease in South Africa

“…Our data on pilus island distribution are comparable to the data in the published study by Margarit et al (2009), and the similarities are sufficient to confirm that the serotype and associated pilus island distribution in South Africa is similar to that reported in the USA and Europe, and based on this homogeneity of pilus island distribution, a pilusbased vaccine developed for these industrialized countries will have similar coverage in South Africa. What remains to be determined is whether pressure from such a vaccine can result in the emergence of strains that lack pilus islands as the dominant virulent types as has been witnessed for other pathogens, such as Streptococcus pneumoniae (Bogaert et al, 2005;Singleton et al, 2007).…”

La vacuna neumocócica conjugada heptavalente (Prevenar™): Diferencias en su efectividad en distintas poblaciones

“…Varios ensayos más han evaluado la eficacia de la VNC7v sola o seguida de la vacuna neumocócica polisacárida en la prevención de recurrencia de la otitis media aguda, encontrando ausencia de eficacia 67 o un efecto preventivo discreto [68][69][70] .…”

“…En resumen, los ensayos aleatorizados de la VNC7v, así como los de la vacuna ampliada nonavalente, demuestran que es altamente eficaz frente a ENI por serotipos vacunales 2-3,47,71-72 , de moderada eficacia frente a la neumonía 47,65,72 , y algo eficaz frente a la otitis media aguda 2,12,[67][68][69][70]73 .…”