Background Pneumococcal conjugate vaccines (PCVs) cover only a proportion of disease-causing serotypes. In some settings, population-level introduction of PCVs has resulted in an increase in "non-vaccine" serotype incidence. Higher-valency PCVs were developed to address shifting disease-causing serotypes. We aim to systematically define the trends in vaccine immunogenicity and likely protection over time. Methods We conducted a systematic review and meta-analysis of studies published to Jan 7, 2025, reporting immunoglobulin G (IgG) responses after PCV vaccination in healthy children <2 years. Outcomes were serotype-specific IgG geometric mean concentration (GMC) and seroresponse rate. We performed random-effects meta-analyses using log-transformed GMCs and logit-transformed seroresponse rates to generate pooled estimates by vaccine product, dosing schedule, and World Health Organization (WHO) region. This study was registered with PROSPERO (CRD42024484824). Findings We included 250 articles from 138 study groups involving 244 study arms. Pooled IgG GMCs for vaccine-included serotypes post-childhood-schedule exceeded the WHO-defined protective threshold (0.35 ug/mL), but varied by serotype, lowest for serotype 3-PCV20 (0.84 ug/mL; 95% confidence interval: 0.60–1.17). Post-childhood-schedule seroresponse rates were >95% for all serotypes except serotype 3 (84–92%). A general "downward trend" in IgG GMCs was observed with the increasing vaccine valency. IgG responses increased with the number of primary doses, and were further enhanced by a booster, although magnitude varied by serotype and vaccine. IgG responses post 1-primary dose were low, whereas GMCs post 2- or 3-primary doses exceeded protective thresholds for most serotypes. Booster-containing schedules (3+1, 2+1, 1+1) generally elicited higher post-childhood-schedule IgG response than primary-only schedule (3+0). We observed substantial regional variation of post-childhood-schedule serotype-specific IgG GMCs, with highest GMCs in the Western Pacific Region. Interpretation Vaccine immunogenicity varied by serotype, vaccine product, schedule and WHO region, and should be carefully considered when evaluating potential vaccination programs. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Protocols ### Funding Statement This work received no dedicated funding. XC is supported by the China Scholarship Council–University of Melbourne PhD Scholarship; PTC receives salary support from SPARKLE, funded by the Australian Department for Foreign Affairs and Trade under the Partnerships for a Healthy Region Initiative grant to the Peter Doherty Institute for Infection and Immunity. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study used only openly available human data identified through searches of EMBASE, MEDLINE, Web of Science Core Collection, Global Health, and the Cochrane Central Register of Controlled Trials. No new human data were collected, and no interaction with human subjects occurred. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors
Abstract Background PICOBOO is a randomised, adaptive trial evaluating the immunogenicity, reactogenicity, and safety of COVID-19 booster strategies. Here, we report data for second boosters among individuals aged 18-< 50 and 50-< 70 years old primed with BNT162b2 (18-< 50y-BNT162b2 and 50-< 70y-BNT162b2, respectively) until Day (D) 84. CONSORT diagram for participants recruited to the 18-<50y-BNT162b2 (A) and 50-<70y-BNT162b2 (B) strata for second booster vaccines. Participants were excluded from subsequent analyses if they were infected with COVID-19 (C19 Infection) or had withdrawn. Participants that missed visits (Missed) were eligible to be included in subsequent analyses. CONSORT diagram for participants recruited to the 18-<50y-BNT162b2 (A) and 50-<70y-BNT162b2 (B) strata for second booster vaccines. Participants were excluded from subsequent analyses if they were infected with COVID-19 (C19 Infection) or had withdrawn. Participants that missed visits (Missed) were eligible to be included in subsequent analyses. Methods Immunocompetent adults who received any licensed first booster at least three months prior were eligible. Participants were randomly allocated to BNT162b2, mRNA-1273 or NVX-CoV2373 1:1:1. The log10 concentration of anti-spike IgG was summarised as the geometric mean concentration (GMC). Reactogenicity and safety outcomes were captured. Additional analyses were performed on a subset. ACTRN12622000238774. Baseline characteristics for study participants recruited to the 18-<50y-BNT162b2 and 50-<70y BNT162b2 strata for second booster vaccines summarised according to study arm. Baseline characteristics for study participants recruited to the 18-<50y-BNT162b2 and 50-<70y BNT162b2 strata for second booster vaccines summarised according to study arm. Results Between 29 Mar 2022 and 7 Jul 2023, 743 participants were recruited to the platform with D28 samples; 120 belonged to the 18-< 50y-BNT162b2 and 103 belonged to the 50-< 70y-BNT162b2 strata. At D28, the GMCs (95% credible intervals) were 40 338 (32 978, 47 813), 48 117 (39 603, 57 826) and 24 220 (19 586, 29453) U/L in the 18-< 50y-BNT162b2 stratum following BNT162b2, mRNA-1273 and NVX-CoV2372, respectively. Corresponding values in the 50-< 70y-BNT162b2 stratum were 29 344 (23 763, 35 163), 36 026 (29 042, 43456) and 16 040 (12 923, 19 510) U/L. By D84, GMCs fell to 24 643 (17 779, 31 708), 33 236 (24 078, 42, 798) and 20 898 (14 978, 27 596) in the 18-< 50y-BNT162b2 stratum, respectively. D84 GMCs in the 50-< 70y-BNT162b2 stratum were 19 782 (14 157, 25 771), 24 817 (17 740, 32 024) and 15 310 (11 0349, 19 784) U/mL. At D28, neutralisation against wild-type virus was 172, 211 and 74 IU/mL following BNT162b2, mRNA-1273 and NVX-CoV2372. By D84, this fell to 95, 157 and 72 IU/mL. Limited neutralisation against BA.5 and XBB1.5 was found following all vaccines. Severe reactogenicity events were low (< 5%). Additional data will be available at the time of presentation. Posterior distributions of the anti-spike IgG adjusted GMC against Ancestral SARS-CoV-2 at D7, D28 and D84 for each study arm in participants recruited to the 18-<50y-BNT162b2 and 50-<70y-BNT162b2 strata for second booster vaccines without COVID-19 infection after randomisation and before D28 (D7 for D7 distributions). Posterior distributions of the anti-spike IgG adjusted GMC against Ancestral SARS-CoV-2 at D7, D28 and D84 for each study arm in participants recruited to the 18-<50y-BNT162b2 and 50-<70y-BNT162b2 strata for second booster vaccines without COVID-19 infection after randomisation and before D28 (D7 for D7 distributions). Conclusion Each COVID-19 vaccine elicited boosted antibody responses to wild-type virus among BNT162b2-primed adults. GMCs and neutralisation titres were higher in the younger cohort compared to older adults. Minimal neutralisation was observed against Omicron subvariants, highlighting the need for boosting with vaccines with greater specificity for Omicron subvariants. Posterior distributions of the adjusted geometric mean NF50 of Ancestral SARS-CoV-2 at D28 and D84 for each study arm in participants recruited to the 18-<50y-BNT162b2 and 50-<70y-BNT162b2 strata for second booster vaccines without COVID-19 infection after randomisation and before D28 in the immunological subset. Posterior distributions of the adjusted geometric mean NF50 of Ancestral SARS-CoV-2 at D28 and D84 for each study arm in participants recruited to the 18-<50y-BNT162b2 and 50-<70y-BNT162b2 strata for second booster vaccines without COVID-19 infection after randomisation and before D28 in the immunological subset. Disclosures Magdalena Plebanski, PhD, AstraZeneca: Grant/Research Support Helen Marshall, MD, ILiAD biotechnologies: Grant/Research Support Saul N. Faust, FRCPCH PhD, AstraZeneca: Grant/Research Support|BioNTech: Grant/Research Support|GSK: Grant/Research Support|Iliad Biotechnologies: Grant/Research Support|J&J: Grant/Research Support|J&J: Advisor, no personal payments (all honoraria paid to employing hospital)|Moderna: Grant/Research Support|Novavax: Advisor, no personal payments (all honoraria paid to employing hospital)|Pfizer: Advisor, no personal payments (all honoraria paid to employing hospital)|Sanofi: Grant/Research Support|Sanofi: Advisor, no personal payments (all honoraria paid to employing hospital)|Valneva: Grant/Research Support Peter Richmond, MBBS, ILiAD biotechnologies: Grant/Research Support
Abstract Background PICOBOO is a randomised, adaptive trial evaluating the immunogenicity, reactogenicity, and safety of COVID-19 booster strategies. Here, we report data for second boosters among individuals aged 50-< 70 years old primed with AZD1222 (50-< 70y-AZD1222) until Day (D) 84. CONSORT diagram CONSORT diagram for participants recruited to the 50-<70y-AZD1222 stratum for second booster vaccines. Participants were excluded from subsequent analyses if they were infected with COVID-19 (C19 Infection) or had withdrawn. Participants that missed visits (Missed) were eligible to be included in subsequent analyses. Methods Immunocompetent adults who received any licensed first booster at least three months prior were eligible. Participants were randomly allocated to BNT162b2, mRNA-1273 or NVX-CoV2373 1:1:1. The log10 concentration of anti-spike IgG was summarised as the geometric mean concentration (GMC). Reactogenicity and safety outcomes were captured. Additional analyses were performed on a subset. ACTRN12622000238774. Baseline characteristics for study participants recruited to the 50-<70y-AZD1222 stratum for second booster vaccines summarised according to study arm. Baseline characteristics for study participants recruited to the 50-<70y-AZD1222 stratum for second booster vaccines summarised according to study arm. Results Between 29 Mar 2022 and 2 Aug 2023, 743 participants were recruited and had D28 samples; 155 belonged to the 50-< 70y-AZD1222 stratum. At D28, the mean adjusted GMCs (95% credible intervals) were 20 690 (17 555, 23 883), 23 867 (20 144, 27 604) and 8 654 (7 267, 9 962) U/mL following boosting with BNT162b2, mRNA-1273 and NVX-CoV2372, respectively. By D84, adjusted GMCs fell to 10 976 (8 826, 13 196), 15 779 (12 512, 19 070) and 6 559 (5 220, 7 937) U/mL in each group, respectively. At D28, mean adjusted neutralisation against Ancestral virus was 159, 213 and 75 IU/mL and 100, 156 and 72 IU/mL by D84 in each group. Limited neutralisation against Omicron subvariants BA.5 and XBB.1.5 was found following boosting with all vaccines. Severe reactogenicity events were few (< 4%). Further data will be available at the time of presentation. Posterior distributions of the anti-spike IgG adjusted GMC against Ancestral SARS-CoV-2 at D7, D28 and D84 for each study arm in participants recruited to the 50-<70y-AZD1222 stratum for second booster vaccines without COVID-19 infection after randomisation and before D28 (D7 for D7 distributions). Posterior distributions of the anti-spike IgG adjusted GMC against Ancestral SARS-CoV-2 at D7, D28 and D84 for each study arm in participants recruited to the 50-<70y-AZD1222 stratum for second booster vaccines without COVID-19 infection after randomisation and before D28 (D7 for D7 distributions). Conclusion These are the first randomised clinical trial data globally of the immunogenicity, reactogenicity and safety of second booster (fourth doses) of mRNA and protein subunit COVID-19 vaccines in adults previously primed with two doses of AZD1222. BNT162b2, mRNA-1273 and NVX-CoV2372 were well tolerated and boosted humoral immune responses. Higher binding and neutralising antibodies against Ancestral SARS-CoV-2 were observed following boosting with mRNA vaccines (BNT162b2 and mRNA-1273) compared to NVX-CoV2372 at all time points. Lower neutralising antibody responses were observed against Omicron subvariants BA.5 and XBB.1.5 following all vaccines until Day 84 highlighting the need for boosting with vaccines with greater specificity for Omicron subvariants. Posterior distributions of the adjusted geometric mean NF50 of Ancestral SARS-CoV-2 at D28 and D84 for each study arm in study participants recruited to the 50-<70y-AZD1222 stratum for second booster vaccines without COVID-19 infection after randomisation and before D28 in the immunological subset. Posterior distributions of the adjusted geometric mean NF50 of Ancestral SARS-CoV-2 at D28 and D84 for each study arm in study participants recruited to the 50-<70y-AZD1222 stratum for second booster vaccines without COVID-19 infection after randomisation and before D28 in the immunological subset. Disclosures Magdalena Plebanski, PhD, AstraZeneca: Grant/Research Support Helen Marshall, MD, ILiAD biotechnologies: Grant/Research Support Saul N. Faust, FRCPCH PhD, AstraZeneca: Grant/Research Support|BioNTech: Grant/Research Support|GSK: Grant/Research Support|Iliad Biotechnologies: Grant/Research Support|J&J: Grant/Research Support|J&J: Advisor, no personal payments (all honoraria paid to employing hospital)|Moderna: Grant/Research Support|Novavax: Advisor, no personal payments (all honoraria paid to employing hospital)|Pfizer: Advisor, no personal payments (all honoraria paid to employing hospital)|Sanofi: Grant/Research Support|Sanofi: Advisor, no personal payments (all honoraria paid to employing hospital)|Valneva: Grant/Research Support Peter Richmond, MBBS, ILiAD biotechnologies: Grant/Research Support
Bordetella pertussis continues to circulate globally despite wide-spread vaccination, with an emergent international epidemic in 2024. The resurgence of disease is confounded by the emergence of pertactin-deficient, macrolide-resistant B. pertussis (MRBP) strains in Asia and Europe, which are under-recognised using traditional diagnostic and surveillance methods. This study addressed these gaps by applying a probe-capture hybridisation technique, which enables targeted culture-independent sequencing of genomes (tNGS) directly from respiratory specimens. Seven co-circulating lineages of B. pertussis were identified in Australia, including two associated with MRBP. Eight epidemiologically unrelated and geographically dispersed cases of MRBP in Australia with a A2037G mutation in all three copies of 23S rRNA were documented, three of which were confirmed by phenotypic testing and sequencing of corresponding isolates. The estimated rate of MRBP among B. pertussis PCR positive cases was 4.4%. This study demonstrated the value of tNGS based on target enrichment and probe capture sets designed for respiratory pathogens for public health laboratory surveillance of pertussis. This approach can improve the resolution and completeness of B. pertussis surveillance given the increasing diversity and vaccine evasion capability of this pathogen. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by the NSW Health Prevention Research Support Program grant to the Centre for Infectious Diseases and Microbiology-Public Health. R.R. and T.G. are supported by NHMRC Investigator grants (GNT2018222 and GNT2025445) ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Genomes and metadata were collected by the Microbial Genomics Reference Laboratory at the NSW Health Pathology-Institute of Clinical Pathology and Medical Research under the Western Sydney Local Health District Human Research Ethics and Governance Committee (Project identifier: 2019/PID14240). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Genome sequences generated in the study were uploaded to NCBI SRA and GenBank Database under BioProject: PRJNA1199062 and PRJNA1178746. Individual reads and assembly accessions are provided in Supplementary File S2.
Background & Aims New antiviral approaches are urgently required that target multiple aspects of the hepatitis B virus (HBV) replication cycle to improve rates of functional cure. HBV RNA represents a novel therapeutic target. Here, we programmed Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas13b endonuclease, to specifically target the HBV pregenomic RNA (pgRNA) and viral mRNAs in a novel approach to reduce HBV replication and protein expression. Methods Cas13b CRISPR RNAs (crRNAs) were designed to target multiple regions of HBV pgRNA. Mammalian cells with replication competent wildtype HBV DNA of different genotypes, a HBV stable cell line, a HBV infection model and a hepatitis B surface antigen (HBsAg)-expressing stable cell line were transfected with PspCas13b-blue fluorescent protein (BFP) and crRNAs plasmids and the impact on HBV replication and protein expression was measured. WT HBV DNA, PspCas13b-BFP and crRNA plasmids were simultaneously hydrodynamically injected into mice, and sera HBsAg was measured. PspCas13b mRNA and crRNA were also delivered by lipid nanoparticles (LNP) in a HBsAg-expressing stable cell line and the impact on secreted HBsAg determined. Results Our HBV targeting crRNAs strongly suppressed HBV replication and protein expression in mammalian cells by up to 96% (p<0.0001). HBV protein expression was also reduced in an HBV stable cell line and in the HBV infection model. CRISPR-Cas13b crRNAs reduced HBsAg expression by 50% (p<0.0001) in vivo. LNP-encapsulated PspCas13b mRNA reduced secreted HBsAg by 87% (p=0.0168) in a HBsAg-expressing stable cell line. Conclusions Together, these results show that CRISPR-Cas13b can be programmed to specifically target and degrade HBV RNAs to reduce HBV replication and protein expression, demonstrating its potential as a novel therapeutic option for chronic HBV infection. Impact and implications There is an urgent need for new treatments that target multiple aspects of the HBV replication cycle. Here, we present CRISPR-Cas13b as a novel strategy to target HBV replication and protein expression paving the way for its development as a potential new treatment option for patients living with chronic hepatitis B.
