ORCID Profile
0000-0002-5529-5542
Current Organisation
University of New South Wales
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Publisher: Oxford University Press (OUP)
Date: 28-08-2016
Publisher: Springer Science and Business Media LLC
Date: 29-04-2021
Publisher: Public Library of Science (PLoS)
Date: 26-05-2016
Publisher: American Society for Clinical Investigation
Date: 06-07-2017
Publisher: IEEE
Date: 11-2012
DOI: 10.1109/EMS.2012.56
Publisher: Springer Science and Business Media LLC
Date: 28-04-2022
Publisher: Oxford University Press (OUP)
Date: 03-11-2015
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-12-2021
Abstract: Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has proven highly effective at preventing severe COVID-19. However, the evolution of viral variants, and waning antibody levels over time, raise questions regarding the longevity of vaccine-induced immune protection. Goel et al . examined B and T lymphocyte responses in in iduals who received SARS-CoV-2 messenger RNA vaccines. They performed a 6-month longitudinal study of in iduals who never had SARS-CoV-2 infection compared with people who had recovered from SARS-CoV-2. Humoral and cellular immune memory was observed in vaccinated in iduals, as were functional immune responses against the Alpha (B.1.1.7), Beta (B.1.351), and Delta (B.1.617.2) viral variants. Analysis of T cell activity suggested that robust cellular immune memory may prevent hospitalization by limiting the development of severe disease. —PNK
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.WATRES.2017.10.063
Abstract: Electro-dewatering (EDW) is an alternative emerging and energy-efficient technology that provides improved liquid/solids separations in the dewatering of wastewater sludge. The EDW technology is not only an innovative dewatering method for significantly reducing the volume of wastewater sludge before re-utilization or disposal, but is also a promising emerging method which may potentially be used for decontamination purposes. In this study, the influence of the sludge properties (e.g. electrical conductivity, zeta potential, specific cake resistance, among others) on their mechanical and electrical behaviour in terms of dewaterability and electro-dewaterability, the applied current (current density from 20 to 80 A/m
Publisher: Cold Spring Harbor Laboratory
Date: 11-03-2021
DOI: 10.1101/2021.03.09.21252641
Abstract: Both previous infection and vaccination have been shown to provide potent protection from COVID-19. However, there are concerns that waning immunity and viral variation may lead to a loss of protection over time. Predictive models of immune protection are urgently needed to identify immune correlates of protection to assist in the future deployment of vaccines. To address this, we modelled the relationship between in vitro neutralisation levels and observed protection from SARS-CoV-2 infection using data from seven current vaccines as well as convalescent cohorts. Here we show that neutralisation level is highly predictive of immune protection. The 50% protective neutralisation level was estimated to be approximately 20% of the average convalescent level (95% CI = 14-28%). The estimated neutralisation level required for 50% protection from severe infection was significantly lower (3% of the mean convalescent level (CI = 0.7-13%, p = 0.0004). Given the relationship between in vitro neutralization titer and protection, we then used this to investigate how waning immunity and antigenic variation might affect vaccine efficacy. We found that the decay of neutralising titre in vaccinated subjects over the first 3-4 months after vaccination was at least as rapid as the decay observed in convalescent subjects. Modelling the decay of neutralisation titre over the first 250 days after immunisation predicts a significant loss in protection from SARS-CoV-2 infection will occur, although protection from severe disease should be largely retained. Neutralisation titres against some SARS-CoV-2 variants of concern are reduced compared to the vaccine strain and our model predicts the relationship between neutralisation and efficacy against viral variants. Our analyses provide an evidence-based prediction of SARS-CoV-2 immune protection that will assist in developing vaccine strategies to control the future trajectory of the pandemic.
Publisher: American Society for Clinical Investigation
Date: 26-11-2018
DOI: 10.1172/JCI122466
Publisher: Public Library of Science (PLoS)
Date: 04-05-2017
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.CELL.2018.05.029
Abstract: Heterogeneity is a hallmark feature of the adaptive immune system in vertebrates. Following infection, naive T cells differentiate into various subsets of effector and memory T cells, which help to eliminate pathogens and maintain long-term immunity. The current model suggests there is a single lineage of naive T cells that give rise to different populations of effector and memory T cells depending on the type and amounts of stimulation they encounter during infection. Here, we have discovered that multiple sub-populations of cells exist in the naive CD8
Publisher: Springer Science and Business Media LLC
Date: 17-05-2021
DOI: 10.1038/S41591-021-01377-8
Abstract: Predictive models of immune protection from COVID-19 are urgently needed to identify correlates of protection to assist in the future deployment of vaccines. To address this, we analyzed the relationship between in vitro neutralization levels and the observed protection from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using data from seven current vaccines and from convalescent cohorts. We estimated the neutralization level for 50% protection against detectable SARS-CoV-2 infection to be 20.2% of the mean convalescent level (95% confidence interval (CI) = 14.4-28.4%). The estimated neutralization level required for 50% protection from severe infection was significantly lower (3% of the mean convalescent level 95% CI = 0.7-13%, P = 0.0004). Modeling of the decay of the neutralization titer over the first 250 d after immunization predicts that a significant loss in protection from SARS-CoV-2 infection will occur, although protection from severe disease should be largely retained. Neutralization titers against some SARS-CoV-2 variants of concern are reduced compared with the vaccine strain, and our model predicts the relationship between neutralization and efficacy against viral variants. Here, we show that neutralization level is highly predictive of immune protection, and provide an evidence-based model of SARS-CoV-2 immune protection that will assist in developing vaccine strategies to control the future trajectory of the pandemic.
Publisher: Cold Spring Harbor Laboratory
Date: 30-06-2021
DOI: 10.1101/2021.06.29.21259504
Abstract: A recent study analysed the relationship between neutralising antibody response and protection from SARS-CoV-2 infection across eight vaccine platforms 1 . The efficacy results from a phase 2b/3 trial of a ninth vaccine candidate, CVnCoV (CUREVAC), was announced on 16 June 2021 2 . The low efficacy of this new mRNA vaccine, which showed only 47% protection from symptomatic SARS-CoV-2 infection, was surprising given the high efficacy of two previous mRNA-based vaccines 3,4 . A number of factors have been suggested to play a role in the low efficacy in the CVnCoV study, particularly around the dose and immunogenicity of the vaccine (which uses an unmodified mRNA construct 5,6 ) and the potential role of infection with SARS-CoV-2 variants (which were the dominant strains observed in the CVnCoV trial) 2 .
Publisher: Springer Science and Business Media LLC
Date: 19-02-2021
DOI: 10.1038/S41467-021-21444-5
Abstract: The durability of infection-induced SARS-CoV-2 immunity has major implications for reinfection and vaccine development. Here, we show a comprehensive profile of antibody, B cell and T cell dynamics over time in a cohort of patients who have recovered from mild-moderate COVID-19. Binding and neutralising antibody responses, together with in idual serum clonotypes, decay over the first 4 months post-infection. A similar decline in Spike-specific CD4 + and circulating T follicular helper frequencies occurs. By contrast, S-specific IgG + memory B cells consistently accumulate over time, eventually comprising a substantial fraction of circulating the memory B cell pool. Modelling of the concomitant immune kinetics predicts maintenance of serological neutralising activity above a titre of 1:40 in 50% of convalescent participants to 74 days, although there is probably additive protection from B cell and T cell immunity. This study indicates that SARS-CoV-2 immunity after infection might be transiently protective at a population level. Therefore, SARS-CoV-2 vaccines might require greater immunogenicity and durability than natural infection to drive long-term protection.
Publisher: IEEE
Date: 08-2012
Publisher: Springer Science and Business Media LLC
Date: 02-11-2020
Publisher: American Association for the Advancement of Science (AAAS)
Date: 21-07-2023
Abstract: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection of vaccinated in iduals is increasingly common with the circulation of highly immune evasive and transmissible Omicron variants. Here, we report the dynamics and durability of recalled spike-specific humoral immunity following Omicron BA.1 or BA.2 breakthrough infection, with longitudinal s ling up to 8 months after infection. Both BA.1 and BA.2 infections robustly boosted neutralization activity against the infecting strain while expanding breadth against BA.4, although neutralization activity was substantially reduced for the more recent XBB and BQ.1.1 strains. Cross-reactive memory B cells against both ancestral and Omicron spike were predominantly expanded by infection, with limited recruitment of de novo Omicron-specific B cells or antibodies. Modeling of neutralization titers predicts that protection from symptomatic reinfection against antigenically similar strains will be durable but is undermined by new emerging strains with further neutralization escape.
Publisher: Informa UK Limited
Date: 26-09-2017
Publisher: Cold Spring Harbor Laboratory
Date: 30-03-2023
DOI: 10.1101/2023.03.28.23287848
Abstract: Understanding mucosal antibody responses from SARS-CoV-2 infection and/or vaccination is crucial to develop strategies for longer term immunity, especially against emerging viral variants. We profiled serial paired mucosal and plasma antibodies from: COVID-19 vaccinated only vaccinees (vaccinated, uninfected), COVID-19 recovered vaccinees (convalescent, vaccinated) and in iduals with breakthrough Delta or Omicron BA.2 infections (vaccinated, infected). Saliva from COVID-19 recovered vaccinees displayed improved antibody neutralizing activity, FcγR engagement and IgA compared to COVID-19 uninfected vaccinees. Furthermore, repeated mRNA vaccination boosted SARS-CoV-2-specific IgG2 and IgG4 responses in both mucosa biofluids (saliva and tears) and plasma. IgG, but not IgA, responses to breakthrough COVID-19 variants were d ened and narrowed by increased pre-existing vaccine-induced immunity to the ancestral strain. Salivary antibodies delayed initiation of boosting following breakthrough COVID-19 infection, especially Omicron BA.2, however, rose rapidly thereafter. Our data highlight how pre-existing immunity shapes mucosal SARS-CoV-2-specific antibody responses and has implications for long-term protection from COVID-19.
Publisher: Cold Spring Harbor Laboratory
Date: 13-08-2021
DOI: 10.1101/2021.08.11.21261876
Abstract: A number of SARS-CoV-2 variants of concern (VOC) have been identified that partially escape serum neutralisation activity elicited by current vaccines. Recent studies have also shown that vaccines demonstrate reduced protection against symptomatic infection with SARS-CoV-2 variants. Here we integrate published data on in vitro neutralisation and clinical protection to understand and predict vaccine efficacy against existing SARS-CoV-2 variants. We find that neutralising activity against the ancestral SARS-CoV-2 is highly predictive of neutralisation of the VOC, with all vaccines showing a similar drop in neutralisation to the variants. Neutralisation levels remain strongly correlated with protection from infection with SARS-CoV-2 VOC (r=0.81, p=0.0005). We apply an existing model relating in vitro neutralisation to protection (parameterised on data from ancestral virus infection) and find this remains predictive of vaccine efficacy against VOC once drops in neutralisation to the VOC are taken into account. Modelling of predicted vaccine efficacy against variants over time suggests that protection against symptomatic infection may drop below 50% within the first year after vaccination for some current vaccines. Boosting of previously infected in iduals with existing vaccines (which target ancestral virus) has been shown to significantly increase neutralising antibodies. Our modelling suggests that booster vaccination should enable high levels of immunity that prevent severe infection outcomes with the current SARS-CoV-2 VOC, at least in the medium term.
Publisher: American Society for Clinical Investigation
Date: 20-06-2016
DOI: 10.1172/JCI85996
Publisher: American Society for Clinical Investigation
Date: 10-04-2023
Publisher: Oxford University Press (OUP)
Date: 10-03-2015
Abstract: To review and update the conceptual framework, indicator content and research priorities of the Organisation for Economic Cooperation and Development's (OECD) Health Care Quality Indicators (HCQI) project, after a decade of collaborative work. A structured assessment was carried out using a modified Delphi approach, followed by a consensus meeting, to assess the suite of HCQI for international comparisons, agree on revisions to the original framework and set priorities for research and development. International group of countries participating to OECD projects. Members of the OECD HCQI expert group. A reference matrix, based on a revised performance framework, was used to map and assess all seventy HCQI routinely calculated by the OECD expert group. A total of 21 indicators were agreed to be excluded, due to the following concerns: (i) relevance, (ii) international comparability, particularly where heterogeneous coding practices might induce bias, (iii) feasibility, when the number of countries able to report was limited and the added value did not justify sustained effort and (iv) actionability, for indicators that were unlikely to improve on the basis of targeted policy interventions. The revised OECD framework for HCQI represents a new milestone of a long-standing international collaboration among a group of countries committed to building common ground for performance measurement. The expert group believes that the continuation of this work is paramount to provide decision makers with a validated toolbox to directly act on quality improvement strategies.
Publisher: Wiley
Date: 31-05-2016
DOI: 10.1038/ICB.2016.47
Publisher: Springer Science and Business Media LLC
Date: 22-01-2019
Publisher: Proceedings of the National Academy of Sciences
Date: 14-02-2019
Abstract: The development of the peripheral T cell pool is typically described based on the maturation and survival of cells in the periphery, assuming all cells are created equal and have similar lifespans. We have developed a mouse model in which we can “timest ” CD8 + T cells produced at different ages and track their survival. We find that cells produced early in life persist and contribute to the adult pool. However, the dynamics of cell survival are dependent on the age at which they are produced, leading to a shifting population of cells with age. We propose that heterogeneity in the developmental origins of cells contributes to the phenotypic heterogeneity of in idual cells observed in adult animals.
Publisher: American Society for Clinical Investigation
Date: 22-09-2023
Publisher: Springer Science and Business Media LLC
Date: 24-03-2023
DOI: 10.1038/S41467-023-37176-7
Abstract: Vaccine protection from symptomatic SARS-CoV-2 infection has been shown to be strongly correlated with neutralising antibody titres however, this has not yet been demonstrated for severe COVID-19. To explore whether this relationship also holds for severe COVID-19, we performed a systematic search for studies reporting on protection against different SARS-CoV-2 clinical endpoints and extracted data from 15 studies. Since matched neutralising antibody titres were not available, we used the vaccine regimen, time since vaccination and variant of concern to predict corresponding neutralising antibody titres. We then compared the observed vaccine effectiveness reported in these studies to the protection predicted by a previously published model of the relationship between neutralising antibody titre and vaccine effectiveness against severe COVID-19. We find that predicted neutralising antibody titres are strongly correlated with observed vaccine effectiveness against symptomatic (Spearman $$\\rho$$ ρ = 0.95, p 0.001) and severe (Spearman $$\\rho$$ ρ = 0.72, p 0.001 for both) COVID-19 and that the loss of neutralising antibodies over time and to new variants are strongly predictive of observed vaccine protection against severe COVID-19.
No related grants have been discovered for Arnold Reynaldi.