Publications by authors named "Chi Wai Leung"

Background: The protection conferred by influenza vaccination is generally thought to last less than a year, necessitating annual revaccination. However, the speed with which influenza vaccine effectiveness might decline during a year is unknown, which is of particular importance for locations with year-round influenza activity. We aimed to assess how influenza vaccine effectiveness changes by time intervals between vaccination and admission to hospital, taking advantage of almost year-round circulation of influenza in Hong Kong.

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We conducted a hospital-based test-negative study in Hong Kong to estimate influenza vaccine effectiveness (VE) for the winter of 2017/18. The interim analysis included data on 1,078 children admitted between 4 December 2017 and 31 January 2018 with febrile acute respiratory illness and tested for influenza. We estimated influenza VE at 66% (95% confidence interval (CI): 43-79) overall, and 65% (95% CI: 40-80) against influenza B, the dominant virus type (predominantly B/Yamagata).

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Background: Influenza A(H3N2) viruses circulated for 12 consecutive months in Hong Kong in 2016-2017, peaking in late June and July 2017. The objective of our study was to estimate the effectiveness of influenza vaccination in preventing hospitalizations in children in Hong Kong.

Methods: We conducted a test-negative study between 1 September 2016 and 31 August 2017, enrolling children 6 months to 17 years of age hospitalized for an acute respiratory infection.

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A 2-year-old boy with highly pathogenic avian influenza A(H5N1) virus infection with minimal respiratory symptoms developed encephalitis complicated by obstructive hydrocephalus. Viral RNA was detectable in cerebrospinal fluid. The virus belonged to H5N1 clade 2.

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From 1 September 2015 through 31 January 2016, we enrolled 2068 children 6 months to 17 years of age admitted to hospital with a febrile acute respiratory infection in our test-negative study. Information on receipt of 2015-16 northern hemisphere inactivated influenza vaccination was elicited from parents or legal guardians. Using conditional logistic regression adjusting for age and matching on calendar time, we estimated influenza vaccine effectiveness against hospitalization with influenza A or B to be 79.

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Background: A phase III, double-blind, randomized, controlled trial was conducted in Hong Kong to evaluate the efficacy, safety and immunogenicity of a human rotavirus vaccine, RIX4414 (Rotarix) against severe rotavirus gastroenteritis in children up to three years of age.

Methods: Healthy infants aged 6-12 weeks were enrolled between 08-December-2003 and 31-August-2005 and received two oral doses of either RIX4414 vaccine (N=1513) or placebo (N=1512) given 2 months apart. Vaccine efficacy was assessed from two weeks post-Dose 2 until the children were two and three years of age.

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Objective: The objective of this study was to evaluate the relationship between histological chorioamnionitis and laboratory markers of infection and congenital sepsis in very-low-birth-weight (VLBW) premature neonates.

Method: This study is a retrospective review of laboratory results of VLBW neonates with birth weight less than 1500 g in our neonatal intensive care unit (NICU) in the last 5 years.

Results: Ninety-nine VLBW neonates had histological chorioamnionitis, and 50 of them further had funisitis.

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Viral shedding profile of infections caused by the pandemic H1N1 2009 influenza A virus has not been reported. The aim of this study was to determine the viral load in different body sites. Viral loads of pandemic H1N1 virus in respiratory specimens, stool, urine, and serum were determined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

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Objective: The objective of our study was to report the thin-section CT findings 12 months after the diagnosis of severe acute respiratory syndrome (SARS) in pediatric patients who had recovered clinically but had persistent abnormal CT findings 6 months after the diagnosis. The clinical data for these patients were correlated to identify risk factors that might increase the likelihood of the development of CT abnormalities.

Subjects And Methods: The study involved an extended 12-month thin-section CT follow-up of 16 of 47 pediatrics patients with SARS coronavirus-associated pneumonia proven serologically (21 girls and 26 boys; age range, 1.

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The mortality rate in documented avian influenza A virus subtype H5N1 infection is still high, which is currently reported by WHO at about 50%. Post-mortem analyses in affected patients have revealed haemophagocytosis similar to that found in patients with haemophagocytic lymphohistiocytosis (HLH); such haemophagocytosis could be a very prominent post-mortem feature in H5N1 infection. There are also clinical similarities between H5N1 infection and HLH, such as massive hypercytokinaemia, cytopenia, and acute encephalitis.

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We report the association of painful pustulo-vesicular skin rash with Kawasaki disease. The initial clinical presentation of our patient mimicked chickenpox infection, and the diagnosis was based on the characteristic clinicopathological features and the exclusion of other causes of pustulo-vesicular eruption.

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Unlabelled: Patients with severe acute respiratory syndrome (SARS) may present with extra-pulmonary symptoms. We report a 16-year-old adolescent with SARS who presented with diarrhoea. Treatment directed against SARS was prompted by an epidemiological link and the clinical picture as the disease evolved.

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A 13-year-old boy contracted severe acute respiratory syndrome (SARS). The clinical course was mild, and no specific treatment was given. His recovery was spontaneous and complete.

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Severe acute respiratory syndrome (SARS) is highly contagious. Mandatory home confinement of 10 days has generally been recommended to quarantine close contacts of SARS cases. We report the epidemiologic linkage of SARS within an extended family.

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Objective: To study the epidemiologic, clinical, laboratory, and radiologic features, prognostic indicators, and short-term to medium-term outcomes for children with severe acute respiratory syndrome (SARS) and to validate the performance characteristics of a clinical case definition, calculated with respect to SARS-associated coronavirus (SARS-CoV) seroconversion.

Methods: Children <18 years of age, from a single-site outbreak, who satisfied a clinical case definition for SARS, with subsequent serologic confirmation, were treated according to a standard protocol and prospectively monitored.

Results: Forty-four children were included.

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Background: Severe acute respiratory syndrome (SARS) is a recently recognized condition of viral origin associated with substantial morbidity and mortality rates in adults. Little information is available on its radiologic manifestations in children.

Objective: The goal of this study was to characterize the radiographic presentation of children with SARS.

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