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Gori, A.

Publications and source records attributed to Gori, A..

At least 19 recordsLinked to original sources

AI-Driven Computational Design of Peptide-Based WWP1 Inhibitors as Promising Therapeutic Agents Against Breast Cancer, Including Triple-Negative Subtype

Breast cancer (BC) is the second most common noncutaneous cancer and the second leading cause of cancer-related death in women. BC is classified into three primary subtypes, with triple-negative breast cancer (TNBC) having the poorest prognosis because it lacks specific targetable markers. Preclinical studies on TNBC indicated a common occurrence of diminished tumor-suppressor activity of PTEN, activating the PI3K/AKT/mTOR signaling pathway. Notably, published studies reveal that the WWP1 enzyme plays a pivotal role in driving PTEN degradation via ubiquitination, unveiling a promising therapeutic target for treating TNBC. In the search of new WWP1 inhibitors, we used artificial intelligence (AI)-driven computational strategies for de novo design of peptide-based WWP1 inhibitors and identified a hexapeptide, termed WI23-B, which demonstrated high nanomolar binding affinity to WWP1. In TR-FRET enzymatic assays, WI23-B inhibited WWP1 activity with an IC of approximately 11 {micro}M. In MCF7 and MDA-MB-231 breast cancer cell lines, WI23-B showed promising cytotoxic efficacy, particularly in combination with the PI3K inhibitor BYL719, also when it was loaded into nanocapsules. Collectively, these findings highlight WI23-B as a promising lead peptide with potent WWP1 inhibitory activity and synergistic antiproliferative effects when combined with PI3K inhibitors. While further structural optimization is required to enhance its potency and pharmacological properties, our results provide a strong foundation for the development of next-generation WWP1 inhibitors. Such agents have the potential to reshape therapeutic strategies for BC and TNBC by enabling more effective and less toxic treatment regimens, ultimately reducing the reliance on high-dose chemotherapy and minimizing adverse effects.

cancer biology↗

Enhanced Workflow for Urinary Extracellular Vesicle Isolation Using Membrane-Sensing Peptides

Urinary extracellular vesicles (uEVs) represent a promising source of non-invasive biomarkers; however, their clinical translation is still limited by suboptimal isolation strategies, which often suffer from poor scalability, co-isolation of abundant urinary proteins, and bias toward specific EV subpopulations. Here, we employ a membrane-sensing peptide (MSP)-based affinity approach for uEVs isolation, that exploits the highly lipid membranes curvature of EV as universal target, enabling pan-specific capture independent of surface marker expression. MSP-functionalized beads were applied to minimally processed urine samples and benchmarked against differential ultracentrifugation (dUC) and size-exclusion chromatography (SEC). Comprehensive characterization by nanoparticle tracking analysis, transmission electron microscopy, high-sensitivity flow cytometry, single-molecule array (SiMoA), and fluorescence nanoparticle tracking analysis, demonstrated that MSP-based isolation preserves vesicle integrity and maintains the native distribution of canonical tetraspanins (CD9, CD63, CD81), without evidence of subpopulation bias. Notably, MSP-based isolation significantly reduced co-isolated contaminants, such as uromodulin, resulting in improved sample purity. By combining high recovery, improved purity, and operational simplicity, MSP workflow offers practical advantages, including reduced processing time, scalability, and compatibility with standard laboratory equipment, without the need for extensive pre-processing. These properties characterize MSP-based affinity capture as a robust and versatile alternative to conventional uEVs isolation approaches, with strong potential for translational and clinical applications.

biochemistry↗

A CYFIP1-Inspired Peptidomimetic Modulates eIF4E-Dependent Translational Control in Cancer and Neurodevelopmental Disorders

The eukaryotic translation initiation factor 4E (eIF4E) is a central regulator of cap-dependent translation and a compelling pharmacological target in disorders marked by protein synthesis dysregulation, including cancer and Fragile X Syndrome (FXS). Among endogenous eIF4E regulators, the CYFIP1-eIF4E interaction is uniquely selective, offering a framework for designing targeted translation modulators. Here, we report Cy-9B, a rationally engineered, stapled peptidomimetic derived from CYFIP1 that binds eIF4E, disrupts eIF4E-eIF4G complex, and suppresses cap-dependent translation. Enhanced-sampling free-energy simulations reveal that Cy-9B engages eIF4E through a non-canonical binding mode. Cy-9B exhibits drug-like properties, including high proteolytic stability and nanomolar affinity. Functionally, Cy-9B inhibits lung cancer cell proliferation, migration, and invasion. In neurodevelopmental disease models, Cy-9B partially normalizes excessive translation in FXS hippocampal neurons and rescues social behavior deficits in a Cyfip1 haploinsufficient Drosophila melanogaster model, restoring wild-type-like performance. Cy-9B emerges as a first-in-class therapeutic candidate for disorders sharing translational dysregulation, highlighting targeted modulation of eIF4E as a broadly applicable and physiologically compatible therapeutic strategy.

biochemistry↗

Membrane Sensing Peptides -Enhanced SiMoA Platform for the Detection of HER2 on Extracellular Vesicles in Metastatic Breast Cancer Patients

Extracellular vesicles (EVs) offer a promising avenue for non-invasive, real-time monitoring of metastatic breast cancer (mBC), but clinical application as a liquid biopsy is hindered by their heterogeneity and low abundance. Here we present a Single Molecule Array (SiMoA) platform enhanced by membrane sensing peptides (MSP) for the highly sensitive detection of HER2 on EV membranes (EVs-HER2) and general EVs population (CD9+) directly from plasma samples of mBC patients. The MSP-based SiMoA assay demonstrated superior sensitivity and specificity compared to conventional antibody-based assays, allowing the detection of lower amounts of EVs and discriminating EVs derived from breast cancer patient-derived organoids (BC-PDO) from healthy control-derived organoids (HC-PDO). Concerning the analysis of EVs in plasma samples (n=49 mBC patients, n=30 healthy controls), we observed significantly lower CD9+ EVs levels in mBC patients relative to healthy controls, a trend consistently confirmed across assays. Notably, EVs-HER2 levels were significantly enriched in HER2-positive patients and correlated with clinical HER2 status assessed by immunohistochemistry. Besides, lower CD9+ EVs levels were associated with poorer clinical outcomes, highlighting the potential prognostic utility of EV quantification. Our findings underscore the potential of MSP-enhanced SiMoA platforms for accurate, minimally invasive monitoring of EVs-HER2 in mBC and for monitoring CD9+ EVs levels to assess disease progression.

biochemistry↗

Addressing heterogeneity in direct analysis of Extracellular Vesicles and analogues using Membrane-Sensing Peptides as Pan-Affinity Probes

Extracellular vesicles (EVs), crucial mediators of cell-to-cell communication, hold immense potential for diagnostic applications due to their ability to enrich protein biomarkers in body fluids. However, challenges in isolating EVs from complex biological specimens hinder their widespread use. In this frame, integrated isolation-and-analysis workflows are the go-to strategy, most of which see the prevalence of immunoaffinity methods. Yet, the high heterogeneity of EVs poses challenges, as proposed ubiquitous markers are less homogenously prevalent than believed, raising concerns about the reliability of downstream biomarker discovery programs. This issue extends to the burgeoning field of engineered EV-mimetics and bio-nanoparticles, where conventional immune-affinity methods may lack applicability. Addressing these challenges, we introduce the use Membrane Sensing Peptides (MSP) as "universal" affinity ligands for both EVs and EV-analogues. Employing a streamlined process integrating on-bead capture and vesicle phenotyping through Single Molecule Array (SiMoA) technology, we showcase the application of MSP ligands in the integrated analysis of circulating EVs in blood derivatives, eliminating the need for prior EV isolation. Demonstrating the possible clinical translation of MSP technology, we directly detect an EV-associated epitope signature in serum and plasma samples, demonstrating its potential for distinguishing patients with myocardial infarction versus stable angina. At last, notably, MSP exhibits a unique capability to enable the analysis of tetraspanin-lacking Red Blood Cell derived EVs (RBC-EVs). Overall, unlike traditional antibody-based methods, MSP probes work agnostically, overcoming limitations associated with surface protein abundance or scarcity. This highlights the potential of MSP in advancing EV analysis for clinical diagnostics and beyond. Of note, this represents also the first-ever peptide-based application in SiMoA technology.

biochemistry↗

Is HDL-c plasma concentration a possible marker of HIV replication? A cross-sectional analysis in untreated HIV-infected individuals accessing HIV care in Italy

AimsHIV infection is associated with dyslipidemia and an increased risk for cardiovascular diseases. HIV Nef protein downregulates the generation of nascent HDL. The interplay between HIV-RNA, HDL-c level and CD4/CD8 ratio in naive HIV patients remains to be elucidated. MethodsWe included untreated persons living with HIV (PLWH) of the ICONA Foundation Study cohort if they also had [&ge;]2 viral load (VL) measurements prior to ART initiation. We performed unadjusted correlation and linear regression analyses evaluating the effect of VLset on HDL-C. Vlset and CD4/CD8 ratio were fit in the log10 scale, while HDL-c, was fitted in the untransformed raw scale. ResultsWe included 3,980 untreated PLWH. Fifty-eighty (1.5%) were aviremic. We observed a negative correlation between HDL-c and VLset (Pearson R2=0.03), from fitting an unadjusted linear regression model -8.5 mg/dl (95% CI: -15,9 --0,84 p<0.03). There was a dose-response relationship between HDL-c levels and VLset, however, this association was somewhat attenuated after further controlling for gender. Despite a positive correlation between HDL-c and CD4/CD8 ratio, the HDL-c plasma concentration does not satisfy the criteria for a strong surrogate marker. ConclusionsOur data show that HDL-c plasma concentration is significantly lower per higher level of VLSet although this was in part explained by gender. Further analyses should be promoted to better understand the molecular mechanisms that underline the relationship between HIV replication, HDL-c formation, and diseases progression.

immunology↗

Compositional profiling of extracellular vesicles/lipoproteins mixtures by AFM nanomechanical imaging

The widely overlapping physicochemical properties of lipoproteins (LPs) and extracellular vesicles (EVs) represents one of the main obstacles for the isolation and characterization of these pervasive biogenic lipid nanoparticles. We herein present the application of an atomic force microscopy (AFM)-based quantitative morphometry assay to the rapid nanomechanical screening of mixed LPs and EVs samples. The method can determine the diameter and the mechanical stiffness of hundreds of individual nanometric objects within few hours. The obtained diameters are in quantitative accord with those measured via cryo-electron microscopy (cryo-EM); the assignment of a specific nanomechanical readout to each object enables the simultaneous discrimination of co-isolated EVs and LPs even if they have overlapping size distributions. EVs and all classes of LPs are shown to be characterized by specific combinations of diameter and stiffness, thus making it possible to estimate their relative abundance in EV/LP mixed samples in terms of stoichiometric ratio, surface area and volume. As a side finding, we show how the mechanical behaviour of specific LP classes is correlated to distinctive structural features revealed by cryo-EM. To the best of our knowledge, these results represent the first systematic single-particle mechanical investigation of lipoproteins. The described approach is label-free, single-step and relatively quick to perform. Importantly, it can be used to analyze samples which prove very challenging to assess with several established techniques due to ensemble-averaging, low sensibility to small particles, or both, thus providing a very useful tool for quickly assessing the purity of EV/LP isolates including plasma- and serum-derived preparations.

biophysics↗

Omicron BA.1 and BA.2 neutralizing activity elicited by a comprehensive panel of human vaccines

The SARS-CoV-2 Omicron variant of concern comprises three sublineages designated BA.1, BA.2, and BA.3, with BA.2 steadily replacing the globally dominant BA.1. We show that the large number of BA.1 and BA.2 spike mutations severely dampen plasma neutralizing activity elicited by infection or seven clinical vaccines, with cross-neutralization of BA.2 being consistently more potent than that of BA.1, independent of the vaccine platform and number of doses. Although mRNA vaccines induced the greatest magnitude of Omicron BA.1 and BA.2 plasma neutralizing activity, administration of a booster based on the Wuhan-Hu-1 spike sequence markedly increased neutralizing antibody titers and breadth against BA.1 and BA.2 across all vaccines evaluated. Our data suggest that although BA.1 and BA.2 evade polyclonal neutralizing antibody responses, current vaccine boosting regimens may provide sufficient protection against Omicron-induced disease.

immunology↗

SARS-CoV-2 spike conformation determines plasma neutralizing activity

Numerous safe and effective COVID-19 vaccines have been developed that utilize various delivery technologies and engineering strategies. The influence of the SARS-CoV-2 spike (S) glycoprotein conformation on antibody responses induced by vaccination or infection in humans remains unknown. To address this question, we compared plasma antibodies elicited by six globally-distributed vaccines or infection and observed markedly higher binding titers for vaccines encoding a prefusion-stabilized S relative to other groups. Prefusion S binding titers positively correlated with plasma neutralizing activity, indicating that physical stabilization of the prefusion conformation enhances protection against SARS-CoV-2. We show that almost all plasma neutralizing activity is directed to prefusion S, in particular the S1 subunit, and that variant cross-neutralization is mediated solely by RBD-specific antibodies. Our data provide a quantitative framework for guiding future S engineering efforts to develop vaccines with higher resilience to the emergence of variants and longer durability than current technologies.

immunology↗

Broadly neutralizing antibodies overcome SARS-CoV-2 Omicron antigenic shift

The recently emerged SARS-CoV-2 Omicron variant harbors 37 amino acid substitutions in the spike (S) protein, 15 of which are in the receptor-binding domain (RBD), thereby raising concerns about the effectiveness of available vaccines and antibody therapeutics. Here, we show that the Omicron RBD binds to human ACE2 with enhanced affinity relative to the Wuhan-Hu-1 RBD and acquires binding to mouse ACE2. Severe reductions of plasma neutralizing activity were observed against Omicron compared to the ancestral pseudovirus for vaccinated and convalescent individuals. Most (26 out of 29) receptor-binding motif (RBM)-directed monoclonal antibodies (mAbs) lost in vitro neutralizing activity against Omicron, with only three mAbs, including the ACE2-mimicking S2K146 mAb1, retaining unaltered potency. Furthermore, a fraction of broadly neutralizing sarbecovirus mAbs recognizing antigenic sites outside the RBM, including sotrovimab2, S2X2593 and S2H974, neutralized Omicron. The magnitude of Omicron-mediated immune evasion and the acquisition of binding to mouse ACE2 mark a major SARS-CoV-2 mutational shift. Broadly neutralizing sarbecovirus mAbs recognizing epitopes conserved among SARS-CoV-2 variants and other sarbecoviruses may prove key to controlling the ongoing pandemic and future zoonotic spillovers.

immunology↗

EVs analysis in the COVID-19 era: insights on serum inactivation protocols towards downstream isolation and analysis

Since the outbreak of COVID-19 crisis, the handling of biological samples from confirmed or suspected SARS-CoV-2 positive individuals demanded the use of inactivation protocols to ensure laboratory operators safety. While not standardized, these practices can be roughly divided in two categories, namely heat inactivation and solvent-detergent treatments. As such, these routine procedures should also apply to samples intended for Extracellular Vesicles (EVs) analysis. Assessing the impact of virus inactivating pre-treatments is therefore of pivotal importance, given the well-known variability introduced by different pre-analytical steps on downstream EVs isolation and analysis. Arguably, shared guidelines on inactivation protocols tailored to best address EVs-specific requirements will be needed among the EVs community, yet deep investigations in this direction havent been reported so far. In the attempt of sparking interest on this highly relevant topic, we here provide preliminary insights on SARS-CoV-2 inactivation practices to be adopted prior serum EVs analysis by comparing solvent/detergent treatment vs. heat inactivation. Our analysis entailed the evaluation of EVs recovery and purity along with biochemical, biophysical and biomolecular profiling by means of Nanoparticle Tracking Analysis, Western Blotting, Atomic Force Microscopy, miRNA content (digital droplet PCR) and tetraspanin assessment by microarrays. Our data suggest an increase in ultracentrifugation (UC) recovery following heat-treatment, however accompanied by a marked enrichment in EVs-associated contaminants. On the contrary, solvent/detergent treatment is promising for small EVs (< 150 nm range), yet a depletion of larger vesicular entities was detected. This work represents a first step towards the identification of optimal serum inactivation protocols targeted to EVs analysis.

biochemistry↗

SARS-CoV-2 epitope mapping on microarrays highlights strong immune-response to N protein region

A workflow for SARS-CoV-2 epitope discovery on peptide microarrays is herein reported. The process started with a proteome-wide screening of immunoreactivity based on the use of a high-density microarray followed by a refinement and validation phase on a restricted panel of probes using microarrays with tailored peptide immobilization through a click-based strategy. Progressively larger, independent cohorts of Covid-19 positive sera were tested in the refinement processes, leading to the identification of immunodominant regions on SARS-CoV-2 Spike (S), Nucleocapsid (N) protein and Orf1ab polyprotein. A summary study testing 50 serum samples highlighted an epitope of the N protein (region 155-171) providing 92% sensitivity and 100% specificity of IgG detection in Covid-19 samples thus being a promising candidate for rapid implementation in serological tests.

biochemistry↗

Within-host competition modulates pneumococcal antibiotic resistance in the pre-vaccination era

BackgroundAntibiotic treatment is a key tool in the fight against pneumococcal infections. However, the ongoing emergence of antibiotic resistant strains and high frequencies of antibiotic resistance of pneumococci pose a major public health challenge. How and which ecological and evolutionary mechanisms help maintain the coexistence of strains susceptible and resistant to antibiotic treatment remains largely an open question. Methods/resultsExpanding on a Streptococcus pneumoniae modelling framework, we here explore how both between- and within-host mechanisms of transmission can sustain observed levels of pneumococcal resistance to antibiotics in the pre-vaccination era using a stochastic, individual-based model. Our framework considers that within-host competition for co-colonization between resistant and susceptible strains can arise via pre-existing immunity (immunological competition) or intrinsic fitness differences due to resistance costs (ecological competition). We find that beyond stochasticity, host-population structure or movement at the between-host level, competition at the within-host level can explain observed variation in resistance frequencies. ConclusionIn a series of simulated scenarios informed by observed pneumococcal data in the European region, we demonstrate that ecological competition for co-colonization can explain much of the variation in co-existence observed at the country level in the pre-vaccination era. This work expands our understanding of how within-host pneumococcal competition facilitates the maintenance of antibiotic resistance in the pre-vaccination era. The demonstration of the effects of such underlying, often unmeasured competition-related components of pneumococcal dynamics improves our understanding of the mechanistic drivers for the emergence and maintenance of antibiotic resistance.

ecology↗

Evaluation of pneumococcal serotyping in nasopharyngeal carriage isolates by latex agglutination, whole genome sequencing (PneumoCaT) and DNA microarray in a high pneumococcal carriage prevalence population in Malawi

BackgroundAccurate assessment of the serotype distribution associated with pneumococcal colonization and disease is essential for the evaluation and formulation of pneumococcal vaccines and informing vaccine policy. MethodsWe evaluated pneumococcal serotyping concordance between latex agglutination, PneumoCaT by whole genome sequencing (WGS) and DNA microarray using samples from community carriage surveillance in Blantyre, Malawi. Nasopharyngeal swabs were collected, following WHO recommendations, between 2015 and 2017, using stratified random sampling among study populations. Participants included healthy children 3-6 years old (PCV13 vaccinated as part of EPI), healthy children 5-10 years (age-ineligible for PCV13), and HIV-infected adults (18-40yrs) on ART. For phenotypic serotyping we used a 13-valent latex kit (SSI, Denmark). For genomic serotyping we applied PneumoCaT pipeline to whole genome sequence libraries. For molecular serotyping by microarray we used the BUGS Bioscience DNA microarray. Results1347 samples were analysed. Concordance was 90.7% (95% CI: 89.0-92.2) between latex and PneumoCaT; 95.2% (93.9-96.3) between latex and microarray; and 96.6% (95.5-97.5) between microarray and PneumoCaT. By detecting carried vaccine serotype (VT) pneumococcus in low relative abundance (median 8%), microarray increased VT detection by 31.5% compared to latex serotyping. ConclusionAll three serotyping methods were highly concordant in identifying dominant serotypes. Latex serotyping is accurate in identifying vaccine-serotypes and requires the least expertise and resources for field-implementation and analysis. However, WGS, which adds population structure, and microarray, which adds multiple-serotype carriage, should be considered at regional reference laboratories while investigating the importance of VT in low relative abundance in transmission and disease.

microbiology↗

Hexokinase 2 displacement from mitochondria-associated membranes prompts Ca2+-dependent death of cancer cells

Cancer cells undergo changes in metabolic and survival pathways that increase their malignancy. Isoform 2 of the glycolytic enzyme hexokinase (HK2) enhances both glucose metabolism and resistance to death stimuli in many neoplastic cell types. Here we observe that HK2 locates at mitochondria-endoplasmic reticulum (ER) contact sites called MAMs (Mitochondria-Associated Membranes). HK2 displacement from MAMs with a selective peptide triggers mitochondrial Ca2+ overload caused by Ca2+ release from ER via inositol-3-phosphate receptors (IP3Rs) and by Ca2+ entry through plasma membrane. This results in Ca2+-dependent calpain activation, mitochondrial depolarization and cell death. The HK2-targeting peptide causes massive death of chronic lymphocytic leukemia B cells freshly isolated from patients, and an actionable form of the peptide reduces growth of breast and colon cancer cells allografted in mice without noxious effects on healthy tissues. These results identify a signalling pathway primed by HK2 displacement from MAMs that can be activated as anti-neoplastic strategy.

cancer biology↗

Pan-GWAS of Streptococcus agalactiae highlights lineage specific genes associated with virulence and niche adaptation

Streptococcus agalactiae (Group B streptococcus, GBS) is a coloniser of the gastrointestinal and urogenital tracts, and an opportunistic pathogen of infants and adults. The worldwide population of GBS is characterised by Clonal Complexes (CCs) with different invasive potentials. CC17 for example, is a hypervirulent lineage commonly associated with neonatal sepsis and meningitis, while CC1 is less invasive in neonates and more commonly causes invasive disease in adults with co-morbidities. The genetic basis of GBS virulence and to what extent different CCs have adapted to different host environments remain uncertain. We have therefore applied a pan-genome wide association study approach to 1988 GBS strains isolated from different hosts and countries. Our analysis identified 279 CC-specific genes associated with virulence, disease, metabolism and regulation of cellular mechanisms that may explain the differential virulence potential of particular CCs. In CC17 and CC23 for example, we have identified genes encoding for pilus, quorum sensing proteins, and proteins for the uptake of ions and micronutrients which are absent in less invasive lineages. Moreover, in CC17, carriage and disease strains were distinguished by the allelic variants of 21 of these CC-specific genes. Together our data highlight the lineage-specific basis of GBS niche adaptation and virulence, and suggest that human-associated GBS CCs have largely evolved in animal hosts before crossing to the humans and then spreading clonally.

genomics↗

Diflunisal targets the HMGB1/CXCL12 heterocomplex and blocks immune cell recruitment

Extracellular HMGB1 triggers inflammation following infection or injury, and supports tumorigenesis in inflammation-related malignancies. HMGB1 has several redox states: reduced HMGB1 recruits inflammatory cells to injured tissues forming a heterocomplex with CXCL12 and signaling via its receptor CXCR4; disulfide-containing HMGB1 binds to TLR4 and promotes inflammatory responses. Here we show that Diflunisal, an aspirin-like nonsteroidal anti-inflammatory drug (NSAID) that has been in clinical use for decades, specifically inhibits in vitro and in vivo the chemotactic activity of HMGB1 at nanomolar concentrations, at least in part by binding directly to both HMGB1 and CXCL12 and disrupting their heterocomplex. Importantly, Diflunisal does not inhibit TLR4-dependent responses. Our findings clarify the mode of action of Diflunisal, and open the way to the rational design of functionally specific anti-inflammatory drugs.

biochemistry↗

Determinants of high residual post-PCV13 pneumococcal vaccine type carriage in Blantyre, Malawi: a modelling study.

BackgroundIn November 2011, Malawi introduced the 13-valent pneumococcal conjugate vaccine (PCV13) into the routine infant schedule. Four to seven years after introduction (2015-2018), rolling prospective nasopharyngeal carriage surveys were performed in the city of Blantyre. Carriage of Streptococcus pneumoniae vaccine serotypes (VT) remained higher than reported in developed countries, and VT impact was surprisingly asymmetric across age-groups. A dynamic transmission model was fit to survey data using a Bayesian Markov-chain Monte Carlo approach, to obtain insights into the determinants of post-PCV13 age-specific VT carriage.\n\nResultsAccumulation of naturally acquired immunity with age and age-specific transmission potential were both key to reproducing the observed data. VT carriage reduction peaked sequentially over time, earlier in younger and later in older age-groups. Estimated vaccine efficacy (protection against carriage) was 66.87% (95% CI 50.49-82.26%), similar to previous estimates. Ten-year projected vaccine impact (VT carriage reduction) among 0-9 years old was lower than observed in other settings, at 76.23% (CI 95% 68.02-81.96%), with sensitivity analyses demonstrating this to be mainly driven by a high local force of infection.\n\nConclusionsWe have identified both vaccine-related and host-related determinants of post-PCV13 pneumococcal VT transmission in Blantyre with vaccine impact determined by age-related characteristics of the local force of infection. These findings are likely to be generalisable to other Sub-Saharan African countries in which PCV impact has been lower than desired, and have implications for the interpretation of post-PCV carriage studies and future vaccination programs.

epidemiology↗