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Please cite this paper as: Wong et al. (2012) Cigarette smoking as a risk factor for influenza-associated mortality: evidence from an elderly cohort. Influenza and Other Respiratory Viruses 7(4), 531-539. Background The effects of individual lifestyle factors on the mortality risk after influenza infection have not been explored. Objectives In this study, we assessed the modifying effects of cigarette smoking on mortality risks associated with influenza in a cohort of Hong Kong elders with a follow-up period of 1998-2009. Methods We used the Cox proportional hazards model with time-dependent covariates of weekly proportions of specimens positive for influenza (termed as influenza virus activity), to calculate the hazard ratio of mortality associated with a 10% increase in influenza virus activity for never, ex- and current smokers. Other individual lifestyle and socioeconomic factors as well as seasonal confounders were also added into the models. Results The overall hazard ratio associated with influenza was 1·028 (95% confidence interval, 1·006, 1·051) for all natural cause mortality and 1·035 (1·003, 1·068) for cardiovascular and respiratory mortality. We found that influenza-associated hazard ratio was greater in current and ex-smokers than in never smokers for mortality of all natural causes, cardiovascular and respiratory diseases. Conclusions The findings suggest that smoking might increase influenza-associated mortality risks among elders. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Mak et al. (2012) The impact of pandemic influenza A (H1N1) 2009 on the circulation of respiratory viruses 2009-2011. Influenza and Other Respiratory Viruses 6(3), e6-e10. Surveillance of respiratory viruses has been conducted for many years at the public health laboratory in Hong Kong. With the occurrence of pandemic influenza A (H1N1) 2009, we observed a change in the seasonality of influenza activity with a seemingly corresponding change in the activity of respiratory syncytial virus, parainfluenza virus, and adenovirus during 2009-2011. This phenomenon could most likely be explained by virus interference. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Belshe et al. (2010). Efficacy of live attenuated influenza vaccine in children 6 months to 17 years of age. Influenza and Other Respiratory Viruses 4(3), 141–145. Background It has been suggested that live attenuated influenza vaccine (LAIV) may be less effective in older individuals because of prior wild-type influenza infections. LAIV is currently approved in the United States, South Korea and Hong Kong for individuals 2–49 years of age. Objective To examine data from previously published pediatric studies to determine the efficacy of LAIV in various age groups. Methods Four studies in which the subject age range exceeded 36 months were identified: one 2-year study comparing LAIV with placebo and three 1-year studies comparing LAIV with trivalent inactivated influenza vaccine (TIV). Efficacy against any strain regardless of antigenic similarity to vaccine was analyzed by age; age groups were based on the study design and sample size. A logistic regression model was used to assess whether age, as a continuous variable, was an effect modifier on LAIV efficacy. Results The efficacy of LAIV did not vary with age in children aged 15–84 months compared with placebo or in children aged 6 months to 17 years compared with TIV. Conclusions The available data from prospective, randomized studies in children does not support the concept that prior repeated exposure to influenza, either through wild-type infection or vaccination with live, attenuated or inactivated vaccines, reduces the efficacy of LAIV compared with placebo or TIV. The decreased immunologic responses to LAIV reported in older individuals or those with pre-existing immunity do not appear to translate into reduced protection from influenza in children. [ABSTRACT FROM AUTHOR]