Influenza A(H3N2) Antibody Responses to Standard-Dose Versus Enhanced Influenza Vaccine Immunogenicity in Older Adults and Prior Season's Vaccine Status.

Background: Annual influenza vaccination is recommended for older adults but repeated vaccination with standard-dose influenza vaccine has been linked to reduced immunogenicity and effectiveness, especially against A(H3N2) viruses.

Methods: Community-dwelling Hong Kong adults aged 65-82 years were randomly allocated to receive 2017-2018 standard-dose quadrivalent, MF59-adjuvanted trivalent, high-dose trivalent, and recombinant-HA quadrivalent vaccination. Antibody response to unchanged A(H3N2) vaccine antigen was compared among participants with and without self-reported prior year (2016-2017) standard-dose vaccination.

Comparative Immunogenicity of Several Enhanced Influenza Vaccine Options for Older Adults: A Randomized, Controlled Trial.

Background: Enhanced influenza vaccines may improve protection for older adults, but comparative immunogenicity data are limited. Our objective was to examine immune responses to enhanced influenza vaccines, compared to standard-dose vaccines, in community-dwelling older adults.

Methods: Community-dwelling older adults aged 65-82 years in Hong Kong were randomly allocated (October 2017-January 2018) to receive 2017-2018 Northern hemisphere formulations of a standard-dose quadrivalent vaccine, MF59-adjuvanted trivalent vaccine, high-dose trivalent vaccine, or recombinant-hemagglutinin (rHA) quadrivalent vaccine.

The Effect of Influenza Vaccination History on Changes in Hemagglutination Inhibition Titers After Receipt of the 2015-2016 Influenza Vaccine in Older Adults in Hong Kong.

Background: Immune responses to influenza vaccination can be weaker in older adults than in other age groups. We hypothesized that antibody responses would be particularly weak among repeat vaccinees when the current and prior season vaccine components are the same.

Methods: An observational study was conducted among 827 older adults (aged ≥75 years) in Hong Kong.

The effectiveness of influenza vaccination against medically-attended illnesses in Hong Kong across three years with different degrees of vaccine match, 2014-17.

Background: Influenza vaccination is the most effective intervention to prevent influenza virus infections. Vaccine effectiveness (VE) can vary due to factors such as matching between vaccine strains and prevailing strains, age and other characteristics of the vaccine recipients.

Objective: To evaluate influenza VE against medically-attended illness in different age groups and against specific influenza types/subtypes in Hong Kong.

Factors affecting patient-reported outcomes after red blood cell transfusion in medical patients.

Background: Physical variables like mortality or cardiac events were used to evaluate the requirement of red blood cell (RBC) transfusion. However, patient-reported outcomes (PROs) of blood transfusion recipients were seldom assessed. The health-related quality of life (HRQoL) of patients before and after RBC transfusion was compared in this study.

Immune Responses to Twice-Annual Influenza Vaccination in Older Adults in Hong Kong.

Background: Many health authorities recommend influenza vaccination of older adults to reduce disease burden. We hypothesized that in tropical and subtropical areas with more prolonged influenza seasons, twice-annual influenza vaccination might provide older adults with improved immunity against influenza.

Methods: In 2014-2015, Hong Kong experienced a substantial A(H3N2) winter epidemic with a mismatched vaccine.

A Smart Card-Based Electronic School Absenteeism System for Influenza-Like Illness Surveillance in Hong Kong: Design, Implementation, and Feasibility Assessment.

Background: School-aged children have the highest incidence of respiratory virus infections each year, and transmission of respiratory viruses such as influenza virus can be a major concern in school settings. School absenteeism data have been employed as a component of influenza surveillance systems in some locations. Data timeliness and system acceptance remain as key determinants affecting the usefulness of a prospective surveillance system.

Increases in absenteeism among health care workers in Hong Kong during influenza epidemics, 2004-2009.

Background: Acute respiratory infections (ARI) are a major cause of sickness absenteeism among health care workers (HCWs) and contribute significantly to overall productivity loss particularly during influenza epidemics. The purpose of this study is to quantify the increases in absenteeism during epidemics including the 2009 influenza A(H1N1)pdm09 pandemic.

Methods: We analysed administrative data to determine patterns of sickness absence among HCWs in Hong Kong from January 2004 through December 2009, and used multivariable linear regression model to estimate the excess all-cause and ARI-related sickness absenteeism rates during influenza epidemics.

A Foodborne Outbreak of Gastroenteritis Caused by Vibrio parahaemolyticus and Norovirus through Non-Seafood Vehicle.

Foodborne outbreaks caused by a mixed infection of Vibrio parahaemolyticus and norovirus have rarely been described. We reported a mixed outbreak of Vibrio parahaemolyticus and norovirus causing acute gastroenteritis in 99 staff members of a company in Guangdong, China, in May 2013, following consumption of roasted duck, an uncommon non-seafood vehicle for such mixed infection, in one meal served in the company's catering service. Epidemiological and laboratory findings indicated that a single asymptomatic food handler was the source of both pathogens, and the high rate of infection of both pathogens was exacerbated by the setting's suboptimal food hygiene practice.