Publications by authors named "Raymond T P Lin"

Southeast Asian countries are at the forefront of public health pressures due to a confluence of factors such as population growth, urbanization, environmental pollution, and infectious diseases (re)emergence. Therefore, the ability to be able to conduct research addressing local and regional needs is of paramount importance. As such, biobanking activities, the standardized collection of biological samples, and associated data, developed over the past few decades supporting ongoing biomedical and clinical research, as well as surveillance are of critical importance.

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Background: BBV152 (Covaxin™) is a whole-virion inactivated SARS-CoV-2 vaccine mixed with an immune adjuvant. We aimed to compare immune responses after booster vaccination with heterologous BBV152 versus homologous mRNA vaccine.

Methods: We conducted a randomized, participant-blinded, controlled trial.

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Article Synopsis
  • - A study evaluated the immune responses from two types of booster vaccinations (homologous BNT162b2 and heterologous mRNA-1273) in individuals who had previously received BNT162b2 and had not been infected with SARS-CoV-2.
  • - The results showed that those who received the heterologous booster had significantly higher antibody levels against wild-type SARS-CoV-2 six months after vaccination, and many participants experienced Omicron breakthrough infections regardless of the booster type.
  • - The findings suggest that while booster shots are beneficial, the immune response decreases significantly over time, highlighting the need for timely booster administration before infection surges. !*
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Background: While numerous studies have evaluated the real-world performance of rapid antigen tests (RATs), data on the effect of Omicron sublineages such as XBB and reinfections on RAT performance is limited. We assessed the performance of RATs and factors associated with RAT-negative results among individuals who tested SARS-CoV-2-positive by reverse transcription-polymerase chain reaction (RT-PCR).

Methods: We conducted a retrospective study among Singapore residents who underwent testing for SARS-CoV-2 with RAT (Acon Flowflex or SD Biosensor) and RT-PCR in the same clinical encounter between 9 May 2022 and 21 November 2022.

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  • Researchers sequenced the genomes of two Trichophyton indotineae isolates from patients, highlighting potential connections to overseas water exposure and varying ages.* -
  • There were no significant mutations in key genes related to drug susceptibility, indicating the isolates were susceptible to antifungal treatments.* -
  • The analysis revealed a genetic distance of 92 SNPs between the two isolates, suggesting a close relationship with other South Asian strains, indicating that T. indotineae might be more common than previously recognized.*
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The COVID-19 pandemic led to an initial increase in the incidence of carbapenem-resistant Enterobacterales (CRE) from clinical cultures in South-East Asia hospitals, which was unsustained as the pandemic progressed. Conversely, there was a decrease in CRE incidence from surveillance cultures and overall combined incidence. Further studies are needed for future pandemic preparedness.

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The National Tuberculosis Programme (NTBP) monitors the occurrence and spread of tuberculosis (TB) and multidrug-resistant TB (MDR-TB) in Singapore. Since 2020, whole-genome sequencing (WGS) of isolates has been performed at the National Public Health Laboratory (NPHL) for genomic surveillance, replacing spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeats analysis (MIRU-VNTR). Four thousand three hundred and seven samples were sequenced from 2014 to January 2023, initially as research projects and later developed into a comprehensive public health surveillance programme.

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Identification of the risk factors and the high-risk groups which are most vulnerable is critical in COVID-19 disease management at a population level. Evaluating the efficacy of vaccination against infections is necessary to determine booster vaccination strategies for better protection in high-risk groups. In this study, we recruited 158 mRNA-vaccinated individuals during the Delta wave of SARS-CoV-2 infections in Singapore and examined the antibody profiles of infected individuals.

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Vaccine immunogenicity in transplant recipients can be impacted by the immunosuppressive (IS) regimens they receive. While BNT162b2 vaccination has been shown to induce an immune response in liver transplant recipients (LTRs), it remains unclear how different IS regimens may affect vaccine immunogenicity after a third BNT162b2 dose in LTRs, which is especially important given the emergence of the Omicron sublineages of SARS-CoV-2. A total of 95 LTRs receiving single and multiple IS regimens were recruited and offered three doses of BNT162b2 during the study period.

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In recognition of the morbidity and mortality associated with human immunodeficiency virus (HIV), the Joint United Nations Programme on HIV/acquired immunodeficiency syndrome (AIDS) (UNAIDS) aims to end the epidemic by setting and striving to achieve the ambitious 95-95-95 targets. However, Singapore is still not performing well in the first UNAIDS target. The National HIV Programme (NHIVP) developed this set of recommendations based on an adaptation of major international guidelines from the World Health Organization and the US Centers for Disease Control and Prevention.

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Objectives: The objectives of this study were to describe the coronavirus disease caused by SARS-CoV-2 (COVID-19) reinfection evaluation algorithm used in the early phase of the pandemic in Singapore and analyze the clinical and laboratory characteristics of the cases evaluated.

Methods: We performed a retrospective case-control analysis including all COVID-19 cases evaluated for possible reinfection under the local COVID-19 reinfection evaluation programme between 1 June 2020-30 June 2021. Whole genome sequencing (WGS) was used as confirmatory testing.

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The on-going COVID-19 pandemic has given rise to SARS-CoV-2 clades and variants with differing levels of symptoms and severity. To this end, we aim to systematically elucidate the changes in the pathogenesis as SARS-CoV-2 evolved from ancestral to the recent Omicron VOC, on their mechanisms (e.g.

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Genomic sequencing is essential to track the evolution and spread of SARS-CoV-2, optimize molecular tests, treatments, vaccines, and guide public health responses. To investigate the global SARS-CoV-2 genomic surveillance, we used sequences shared via GISAID to estimate the impact of sequencing intensity and turnaround times on variant detection in 189 countries. In the first two years of the pandemic, 78% of high-income countries sequenced >0.

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Monkeypox virus (MPXV), which causes disease in humans, has for many years been restricted to the African continent, with only a handful of sporadic cases in other parts of the world. However, unprecedented outbreaks of monkeypox in non-endemic regions have recently taken the world by surprise. In less than 4 months, the number of detected MPXV infections has soared to more than 48,000 cases, recording a total of 13 deaths.

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On June 21, 2022, Singapore reported its second ever case of imported monkeypox and first linked to the ongoing multi-country outbreak that has since been declared a public health emergency of international concern. There was quick initiation of public health measures including identification and quarantine of contacts, with post-exposure smallpox vaccination.

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Article Synopsis
  • Understanding age influences vaccine response is key for effective SARS-CoV-2 vaccine design.
  • In a study of 312 people vaccinated with the BNT162b2 vaccine, most showed strong antibody and T cell responses, although antibody effectiveness decreased against Delta and Omicron variants.
  • Older adults (≥60 years) had lower antibody responses but developed longer-lasting immunity over six months, and a third vaccine dose significantly improved their antibody responses against all variants.
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Understanding the circumstances that lead to pandemics is important for their prevention. We analyzed the genomic diversity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) early in the coronavirus disease 2019 (COVID-19) pandemic. We show that SARS-CoV-2 genomic diversity before February 2020 likely comprised only two distinct viral lineages, denoted "A" and "B.

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IDentif.AI-x, a clinically actionable artificial intelligence platform, was used to rapidly pinpoint and prioritize optimal combination therapies against COVID-19 by pairing a prospective, experimental validation of multi-drug efficacy on a SARS-CoV-2 live virus and Vero E6 assay with a quadratic optimization workflow. A starting pool of 12 candidate drugs developed in collaboration with a community of infectious disease clinicians was first narrowed down to a six-drug pool and then interrogated in 50 combination regimens at three dosing levels per drug, representing 729 possible combinations.

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Background: Over 2021, COVID-19 vaccination programs worldwide focused on raising population immunity through the primary COVID-19 vaccine series. In Singapore, two mRNA vaccines (BNT162b2 and mRNA-1273) and the inactivated vaccine CoronaVac are currently authorized under the National Vaccination Programme for use as the primary vaccination series. More than 90% of the Singapore population has received at least one dose of a COVID-19 vaccine as of December 2021.

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  • Carbapenemase-producing Enterobacterales (CPE) infections in hospitals are thought to spread mainly from detected carriers to other patients in the same ward, but there is limited information on how plasmid-mediated transmission occurs at a larger scale.
  • A study conducted in Singapore over 4.7 years analyzed 779 patients with CPE, finding that 42% of cases were due to clonal transmission, while 44.8% were linked to plasmid-mediated transmission.
  • The results indicated that while direct contact in wards saw a decrease in transmission, indirect contacts (with no overlapping admission periods) remained high, highlighting the need for new strategies to tackle both clonal and plasmid-based infections in hospitals, as the latter
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Article Synopsis
  • The study examines the efficacy of different COVID-19 vaccine booster combinations to enhance immune response against the Omicron variant, addressing concerns about decreasing antibody levels after vaccination and the emergence of variants.
  • A total of 100 individuals who initially received the BNT162b2 vaccine were randomly assigned to receive either a homologous booster (BBB) or a heterologous mRNA-1273 booster (BBM), with antibody levels measured 28 days after the booster.
  • Findings revealed that the heterologous booster (BBM) led to significantly higher levels of neutralizing antibodies compared to the homologous booster (BBB), particularly in older adults, highlighting the potential benefits of mixed vaccine approaches for improved protection against emerging variants.
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Background: In Singapore, quarantine of all close contacts with entry and exit polymerase chain reaction testing enabled evaluation of the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and pediatric age on transmission of the Delta variant.

Methods: This retrospective cohort study included all household close contacts between 1 March 2021 and 31 August 2021.

Results: Among 8470 Delta variant-exposed contacts linked to 2583 indices, full-vaccination of the index with BNT162b2 or mRNA-1273 was associated with reduction in acquisition by contacts (adjusted odds ratio [aOR], 0.

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