Calvin Ka-Fung Lo

Dr. Calvin Ka-Fung Lo

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 December 2017 in Cochrane Database of Systematic Reviews
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Journal Article
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JGJoshua Z Goldenberg
Joshua Z Goldenberg
CYChristina Yap
Christina Yap
LLLyubov Lytvyn
Lyubov Lytvyn
CLCalvin Ka-Fung Lo
Calvin Ka-Fung Lo
JBJennifer Beardsley
Jennifer Beardsley
BJBradley Johnston
Bradley Johnston

2 August 2019 in BMC Infectious Diseases
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Journal Article
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FFfor the FLURISK-INVESTIGATORS
for the FLURISK-INVESTIGATORS
DMDominik Mertz
Dominik Mertz
CLCalvin Ka-Fung Lo
Calvin Ka-Fung Lo
LLLyubov Lytvyn
Lyubov Lytvyn
JOJustin R. Ortiz
Justin R. Ortiz
MLMark Loeb
Mark Loeb
WHO identifies pregnant women to be at increased risk for severe outcomes from influenza virus infections and recommends that they be prioritized for influenza vaccination. The evidence supporting this, however, is inconsistent. Ecologic studies in particular suggest more severe outcomes from influenza infection during pregnancy than studies based on individual patient data. Individual studies however may be underpowered and, as reported in a previous systematic review, confounding factors could not be adjusted for. We therefore conducted an individual participant data meta-analysis to assess the risk for severe outcomes of influenza infection in pregnant women while adjusting for other prognostic factors. We contacted authors of studies included in a recently published systematic review. We pooled the individual participant data of women of reproductive age and laboratory confirmation of influenza virus infection. We used a generalized linear mixed model and reported odds ratios (OR) and 95% confidence intervals (CI). A total of 33 datasets with data on 186,656 individuals were available, including 36,498 eligible women of reproductive age and known pregnancy status. In the multivariable model, pregnancy was associated with a 7 times higher risk of hospital admission (OR 6.80, 95%CI 6.02–7.68), among patients receiving medical care as in- or outpatients, pregnancy was associated with a lower risk of admission to intensive care units (ICU; OR 0.57, 95%CI 0.48–0.69), and was not significantly associated with death (OR 1.00, 95%CI 0.75–1.34). Our study found a higher risk of influenza associated hospitalization among pregnant women as compared to non-pregnant women. We did not find a higher mortality rate or higher likelihood of ICU admission among pregnant women who sought medical care. However, this study did not address whether a true community based cohort of pregnant women is at higher risk of influenza associated complications.

26 April 2018 in Infection Control & Hospital Epidemiology
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BJBradley Johnston
Bradley Johnston
LLLyubov Lytvyn
Lyubov Lytvyn
CLCalvin Ka-Fung Lo
Calvin Ka-Fung Lo
Stephen J. AllenStephen J. Allen
Stephen J. Allen
DWDuolao Wang
Duolao Wang
DMDominik Mertz
Dominik Mertz
OBJECTIVE: To determine whether probiotic prophylaxes reduce the odds of Clostridium difficile infection (CDI) in adults and children.DESIGN: Individual participant data (IPD) meta-analysis of randomized controlled trials (RCTs), adjusting for risk factors.METHODS: We searched 6 databases and 11 grey literature sources from inception to April 2016. We identified 32 RCTs (n=8,713); among them, 18 RCTs provided IPD (n=6,851 participants) comparing probiotic prophylaxis to placebo or no treatment (standard care). One reviewer prepared the IPD, and 2 reviewers extracted data, rated study quality, and graded evidence quality.RESULTS: Probiotics reduced CDI odds in the unadjusted model (n=6,645; odds ratio [OR] 0.37; 95% confidence interval [CI], 0.25–0.55) and the adjusted model (n=5,074; OR, 0.35; 95% CI, 0.23–0.55). Using 2 or more antibiotics increased the odds of CDI (OR, 2.20; 95% CI, 1.11–4.37), whereas age, sex, hospitalization status, and high-risk antibiotic exposure did not. Adjusted subgroup analyses suggested that, compared to no probiotics, multispecies probiotics were more beneficial than single-species probiotics, as was using probiotics in clinical settings where the CDI risk is ≥5%. Of 18 studies, 14 reported adverse events. In 11 of these 14 studies, the adverse events were retained in the adjusted model. Odds for serious adverse events were similar for both groups in the unadjusted analyses (n=4,990; OR, 1.06; 95% CI, 0.89–1.26) and adjusted analyses (n=4,718; OR, 1.06; 95% CI, 0.89–1.28). Missing outcome data for CDI ranged from 0% to 25.8%. Our analyses were robust to a sensitivity analysis for missingness.CONCLUSIONS: Moderate quality (ie, certainty) evidence suggests that probiotic prophylaxis may be a useful and safe CDI prevention strategy, particularly among participants taking 2 or more antibiotics and in hospital settings where the risk of CDI is ≥5%.TRIAL REGISTRATION: PROSPERO 2015 identifier: CRD42015015701Infect Control Hosp Epidemiol 2018;771–781

6 May 2024 in JAC-Antimicrobial Resistance
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CLCalvin Ka-Fung Lo
Calvin Ka-Fung Lo
ASAshwin Sritharan
Ashwin Sritharan
JZJiesi Zhang
Jiesi Zhang
NLNicole Li
Nicole Li
CZCindy Zhang
Cindy Zhang
ABAnthony D Bai
Anthony D Bai
Background: The cefazolin inoculum effect (CzIE) is a phenomenon whereby some MSSA isolates demonstrate resistance to cefazolin when a high bacterial inoculum is used for susceptibility testing. The clinical significance of this phenotypic phenomenon remains unclear. We conducted a systematic review to answer the following question: In patients with serious MSSA infection treated with cefazolin, does infection due to CzIE-positive MSSA isolates result in worse clinical outcomes than infection due to CzIE-negative MSSA isolates? Methods: Ovid MEDLINE, Embase, Cochrane CENTRAL, medRxiv and bioRxiv were searched from inception until 12 April 2023. Studies were included if they tested for CzIE in clinical isolates from MSSA infections in humans. Two independent reviewers extracted data and conducted risk-of-bias assessment. Main outcomes were treatment failure and mortality. Pooling of study estimates was not performed given the heterogeneity of patient populations and outcome definitions. Results: Twenty-three observational studies were included. CzIE presence amidst MSSA isolates ranged from 0% to 55%. There was no statistically significant mortality difference in two studies that compared MSSA infections with and without CzIE, with ORs ranging from 0.72 to 19.78. Of four studies comparing treatment failure, ORs ranged from 0.26 to 13.00. One study showed a significantly higher treatment failure for the CzIE group, but it did not adjust for potential confounders. Conclusions: The evidence on CzIE is limited by small observational studies. In these studies, CzIE did not predict higher mortality in MSSA infections treated with cefazolin. Our findings do not support CzIE testing in clinical practice currently.

22 October 2024 in Journal of Medical Microbiology
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Journal Article
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CLCalvin Ka-Fung Lo
Calvin Ka-Fung Lo
DPDale Purych
Dale Purych
ISInna Sekirov
Inna Sekirov
JKJaswinder Khattra
Jaswinder Khattra
THTrevor J. Hird
Trevor J. Hird
SMShazia Masud
Shazia Masud
We evaluated the Xpert MTB/Rif Ultra assay performance for Mycobacterium tuberculosis (MTB) detection in formalin-fixed paraffin-embedded tissue (FFPET) compared to mycobacterial culture or laboratory-developed MTB PCR test (LDT). FFPET samples with histological features suggestive of tuberculosis from 2018 to 2023 were selected. Five hundred microlitres of tissue lysis buffer was added to FFPET scrolls and incubated at 75 °C for 5 min. After adding 50 µl of proteinase K and overnight incubation at 56 °C, sample aliquots were processed as per the manufacturer’s instructions. MTB culture or LDT assay results were used as a reference for sensitivity and specificity calculations. Of 51 eligible FFPET, 32 were positive for MTB either by culture or LDT PCR on FFPET. Xpert MTB/Rif Ultra detected MTB in 23/32 positive specimens [71.9%, 95% confidence interval (CI) 54.6–84.4%]. Of nine discordant specimens, seven were MTB positive by culture and two were identified by LDT MTB PCR only, as no specimen was submitted for MTB culture. Of 19 negative samples, 100% specificity (95% CI 83.2–100.0%) was attained via Xpert MTB/Rif Ultra. Implementation of Xpert MTB/Rif Ultra on FFPET within clinical laboratories is promising, given its improved turnaround time compared to MTB culture and ability to detect MTB in cases where no tissue is available for culture.

20 October 2017 in Influenza and Other Respiratory Viruses
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CLCalvin Ka-Fung Lo
Calvin Ka-Fung Lo
DMDominik Mertz
Dominik Mertz
MLMark Loeb
Mark Loeb
Background: High‐quality reporting of outbreak characteristics is fundamental to understand the behaviour of various strains of influenza virus and the impact of outbreak management strategies. However, few studies have systematically evaluated the quality of outbreak reporting.Objectives: To conduct a systematic analysis and assessment for reporting quality of influenza outbreaks based on a modified version of the STROBE statement, and to examine characteristics associated with reporting quality.Methods: A literature search was conducted across 3 online databases (PubMed, Web of Science, MEDLINE) for reports of influenza outbreaks (pandemic H1N1, avian, seasonal). The quality of reports meeting our eligibility criteria was assessed using the Modified STROBE criteria and assigned a score of 30. Mean differences (MD) and 95% confidence intervals (CI) were reported for comparisons of study characteristics.Results: Sixty‐four outbreak reports were available for analyses. The average Modified STROBE score was 20/30. Peer‐reviewed articles were associated with a better quality of reporting (MD 2.79, 95% CI 0.79‐4.78). Likewise, reports from authors affiliated with public health agencies were associated with better quality than those from academic institutions (MD 1.65, 95% CI−0.27‐3.56).Conclusions: The development of explicit reporting guidelines specifically geared towards reporting of outbreak investigations proved to be useful. Providing information on patient characteristics, investigation details in introduction and results, as well as addressing limitations that could have biased the findings, were frequently missing in the published reports.