Association of ambient PM2.5 concentration with tuberculosis reactivation diseases-an integrated spatio-temporal analysis.

Objectives: While the plausible role of ambient particulate matter (PM)2.5 exposure in tuberculosis (TB) reactivation has been inferred from in vitro experiments, epidemiologic evidence is lacking. We examined the relationship between ambient PM2.5 concentration and pulmonary TB (PTB) in an intermediate TB endemicity city dominated by reactivation diseases. Methods: Spatio-temporal analyses were performed on TB notification data and satellite-based annual mean PM2.5 concentration in Hong Kong. A total of 52,623 PTB cases from 2005-2018 were mapped to over 400 subdistrict units. PTB standardized notification ratio by population subgroups (elderly aged ≥65, middle-aged 50-64, and young adults aged 15-49) was calculated and correlated with ambient PM2.5 concentration. Results: Significant associations were detected between high ambient PM2.5 concentration and increased PTB among the elderly. Such associations were stable to the adjustment for socio-economic factors and other criteria pollutants. Unstable patterns of association between PM2.5 and PTB risk were observed in the middle-aged population and young adults, for which the observed associations were confounded by other criteria pollutants. Conclusion: With elderly PTB almost exclusively attributable to reactivation, our findings suggested that increased TB reactivations have occurred in association with high ambient PM2.5 exposure, lending support to preventive measures that minimize PM2.5-related TB reactivation.

Hepatitis B burden and population immunity in a high endemicity city - a geographically random household epidemiology study for evaluating achievability of elimination.

This study aimed to provide reference for evaluating the achievability of hepatitis B virus (HBV) elimination in a high endemicity city with universal neonatal vaccination in place for over 30 years. Between September 2018 and October 2020, 2085 citizens from 1143 geographically random households in Hong Kong completed a questionnaire and had blood-testing for HBV markers (anti-HBs, HBsAg, anti-HBc, HBeAg). We evaluated the epidemiology and examined factors associated with HBV exposure, vaccination and chronic diseases. The proportion of households with HBsAg positive index participants was 9.2% (95% CI 7.5%-10.9%). The age- and sex-adjusted HBsAg prevalence was 6.3% (95% CI 5.3%-7.4%), compared to >10% in those born in 1960-1970 and among non-local born citizens, and <1% in people born after introduction of neonatal vaccination. Among 155 HBsAg positive participants, 59% were aware of their infection status with 10% on treatment and 10/150 (6.7%) HBeAg positive. More than 40% (872/2064) tested negative for both HBsAg and anti-HBs, contributed by the lack of immunity in older adults and the waning immunity of vaccines. Hong Kong has remained at high-intermediate HBV endemicity state. The moderate level of anti-HBs positivity and very low treatment coverage (10%) among HBsAg positive participants pose challenges for achieving the HBV elimination target.

Low level of dengue infection and transmission risk in Hong Kong: an integrated analysis of temporal seroprevalence results and corresponding meteorological data.

Hong Kong is an Asia-Pacific City with low incidence but periodic local outbreaks of dengue. A mixed-method assessment of the risk of expansion of dengue endemicity in such setting was conducted. Archived blood samples of healthy adult blood donors were tested for anti-dengue virus IgG at 2 time-points of 2014 and 2018/2019. Data on the monthly notified dengue cases, meteorological and vector (ovitrap index) variables were collected. The dengue virus (DENV) IgG seroprevalence of healthy adults in 2014 was 2.2% (95%C.I. = 1.8-2.8%, n = 3827) whereas that in 2018/2019 was 1.7% (95%C.I. = 1.2-2.3%, n = 2320). Serotyping on 42 sera in 2018/2019 showed that 22 (52.4%) were DENV-2. In 2002-2019, importation accounted for 95.3% of all reported cases. By wavelet analysis, local cases were in weak or no association with meteorological and vector variables. Without strong association between local cases and meteorological/vector variables, there was no evidence of increasing level of dengue infection in Hong Kong.

Seasonality of tuberculosis in intermediate endemicity setting dominated by reactivation diseases in Hong Kong.

Summer-spring predominance of tuberculosis (TB) has been widely reported. The relative contributions of exogenous recent infection versus endogenous reactivation to such seasonality remains poorly understood. Monthly TB notifications data between 2005 and 2017 in Hong Kong involving 64,386 cases (41% aged ≥ 65; male-to-female ratio 1.74:1) were examined for the timing, amplitude, and predictability of variation of seasonality. The observed seasonal variabilities were correlated with demographics and clinical presentations, using wavelet analysis coupled with dynamic generalised linear regression models. Overall, TB notifications peaked annually in June and July. No significant annual seasonality was demonstrated for children aged ≤ 14 irrespective of gender. The strongest seasonality was detected in the elderly (≥ 65) among males, while seasonal pattern was more prominent in the middle-aged (45-64) and adults (30-44) among females. The stronger TB seasonality among older adults in Hong Kong suggested that the pattern has been contributed largely by reactivation diseases precipitated by defective immunity whereas seasonal variation of recent infection was uncommon.

The continuum of influenza vaccine hesitancy among nursing professionals in Hong Kong.

INTRODUCTION: Influenza vaccine hesitancy among healthcare workers poses challenges to the achievement of herd immunity and causes infection risks to vulnerable patients. This study aimed to quantify the extent of influenza vaccine hesitancy among nurses in Hong Kong, to delineate its pattern, and to explore its socio-demographic, professional and personal correlates. METHOD: Nurses in Hong Kong were recruited in a cross-sectional study involving the administration of an online questionnaire survey after the 2017/18 winter influenza season. Respondents' influenza vaccination behaviours, attitudes and psychological antecedents were assessed, followed by their delineation into subgroups along the hesitancy continuum through a combination of multiple correspondence analysis and K-means cluster analysis. Socio-demographic, professional and personal correlations of subgrouping were investigated using generalised ordered logistic regression. RESULTS: The overall vaccination coverage of nurses for the 2017/18 influenza season was 44%. Five clusters were differentiated by the level of influenza vaccine hesitancy: "Very high hesitancy-to-complete refusal" (n = 56; 7%) characterised by outright refusal of vaccination; "High hesitancy" (n = 171; 23%) distinguished by tendency of skipping vaccination and scepticism about safety of vaccine; "Moderate hesitancy" (n = 273; 36%) with uncertainties towards vaccination, mistrust of the government's vaccine recommendations and priority concern on affordability of vaccine; "Low hesitancy" (n = 95; 13%) with cautious acceptance towards vaccination and "No-to-minimal hesitancy" (n = 158; 21%) with strong vaccine confidence and compliance greatly linked to convenience of vaccine access. Nurses having completed at least 3 years' pre-registration professional training, having most family members vaccinated against influenza, and with influenza vaccination history during studentship were less vaccine hesitant. CONCLUSION: With more than half of the nurses in Hong Kong having moderate or higher level of influenza vaccine hesitancy, interventions customised to the needs of nurses as reflected from the characteristics of clusters along the vaccine hesitancy continuum could form an important strategy for improving vaccination uptake.