David Goldblatt, United Kingdom

Presenter of 1 Presentation

PNEUMOCOCCAL CARRIAGE AND ANTIBODY PERSISTENCE FOLLOWING PCV13 DELIVERED AS ONE PRIMARY AND ONE BOOSTER (1+1) VERSUS TWO PRIMARY DOSES AND A BOOSTER IN UK INFANTS (ID 900)

Author Of 10 Presentations

THE EMERGENCE OF A STREPTOCOCCUS PNEUMONIAE SEROTYPE 3 VARIANT CARRIAGE IN THE 8 YEARS FOLLOWING POST-PCV13 INTRODUCTION IN BLANTYRE, MALAWI. (ID 606)

Abstract

Background

Several studies have demonstrated limited PCV13 efficacy against carriage of serotype 3 Streptococcus pneumoniae. In Blantyre, no direct vaccine effect was identified on serotype 3 carriage 8 years after PCV13 introduction, and population-based serology showed limited induction of serotype 3-specific antibodies by vaccine or natural exposure. We hypothesised that sequence variability of the CPS locus could at least partly explain these observations.

Methods

CPS loci of 540 serotype 3 isolates (from Africa, Asia, Europe and America) were analysed. ML-phylogeny, antimicrobial resistance (tetM, mefA, ermB, cat gene presence and pbpX allelic profiles) and MLST were calculated. Colony morphology was assessed in microaerophilic and anaerobic conditions.

Results

We identified a serotype 3 CPS locus variant in 82% of Blantyre isolates (2015-2019), characterized by an 8-gene cluster deletion but unchanged colony morphology. This variant appeared independently in at least 3 distinct phylogenetic clusters, including ST700 and ST3214. These strains are characterised by the presence of AMR genes and higher MIC to penicillin. The missing CPS genes have hypothetical protein annotation.

Conclusions

This CPS variant segregated with an AMR genotype, which may have contributed to its emergence. Whether this CPS variation will influence immunogenicity remains to be determined.

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HEAD-TO-HEAD COMAPRISON OF TEN-VALENT (PCV10) AND 13-VALENT (PCV13) PNEUMOCOCCAL CONJUGATE VACCINE FOLLWING TWO-DOSE PRIMARY SERIES AND AFTER BOOSTER- DOSE IN SOUTH AFRICA: RANDOMISED CONTROLED TRIAL (ID 1164)

RAPID WANING OF VACCINE-INDUCED IMMUNITY AMONG PCV13-VACCINATED CHILDREN UNDER 5 YEARS OLD IN MALAWI WITH SUBSEQUENT ACQUISITION OF NATURAL ANTIBODY THROUGH NATURAL EXPOSURE (ID 267)

PNEUMOCOCCAL CARRIAGE AND ANTIBODY PERSISTENCE FOLLOWING PCV13 DELIVERED AS ONE PRIMARY AND ONE BOOSTER (1+1) VERSUS TWO PRIMARY DOSES AND A BOOSTER IN UK INFANTS (ID 900)

PNEUMOCOCCAL CONJUGATE VACCINE DOSE-RANGING STUDIES IN HUMANS: A SYSTEMATIC REVIEW (ID 268)

Abstract

Background

Reduced dose vaccination with pneumococcal conjugate vaccines may protect against infection. We sought to examine the relationship between the dose of polysaccharide in conjugate vaccines (PCVs) and immunogenicity.

Methods

A systematic review of English publications that evaluated variable dose immunogenicity of PCVs in humans was performed in Medline and Embase databases (Ovid SP) in August 2019. Results were synthesised descriptively due to the heterogeneity of product valency, content and vaccine schedule.

Results

We identified 1691 articles after de-duplication; 9 studies met our inclusion criteria; 2 in adults, 6 in children and 1 in both. Doses of polysaccharide evaluated ranged from 0.44 mcg to 17.6 mcg. Thirty days after vaccination following a single dose or 2p+1 schedule, all doses tested in infants achieved mean IgG concentrations (GMCs) above the acceptable correlate of protection (COP; 0.35 mcg) and only three GMCs' 95% confidence intervals crossed the COP. All doses tested in adults achieved GMCs that were comparable to those considered protective in children who have received 3 standard vaccine doses.

Conclusions

For some products, the mean antibody concentrations induced for some pneumococcal serotypes increased with increasing doses of the polysaccharide but the functional significance of these is uncertain.

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IMMUNOGENICITY OF REDUCED AND ALTERNATE DOSE SCHEDULE (1+1) OF PCV10 (SYNFLORIX) & PCV13 (PREVENAR 13) IN INDIAN INFANTS (ID 1099)

HIGH LEVELS OF LUNG PNEUMOCOCCAL CAPSULAR-SPECIFIC IGG TO MOST VACCINE-TYPE SEROTYPES, BUT SEROTYPE 3, IN ADULTS VACCINATED WITH PCV13 (ID 577)

IMMUNOGENICITY OF SINGLE COMPARED TO TWO-DOSE PRIMARY SERIES FOLLOWED BY BOOSTER DOSE OF 13-VALENT PNEUMOCOCCAL CONJUGATE VACCINE (PCV) IN SOUTH AFRICA: OPEN-LABEL, RANDOMISED, NON-INFERIORITY TRIAL (ID 1153)