Pandemic fatigue impedes mitigation of COVID-19 in Hong Kong.

Hong Kong has implemented stringent public health and social measures (PHSMs) to curb each of the four COVID-19 epidemic waves since January 2020. The third wave between July and September 2020 was brought under control within 2 m, while the fourth wave starting from the end of October 2020 has taken longer to bring under control and lasted at least 5 mo. Here, we report the pandemic fatigue as one of the potential reasons for the reduced impact of PHSMs on transmission in the fourth wave. We contacted either 500 or 1,000 local residents through weekly random-digit dialing of landlines and mobile telephones from May 2020 to February 2021. We analyze the epidemiological impact of pandemic fatigue by using the large and detailed cross-sectional telephone surveys to quantify risk perception and self-reported protective behaviors and mathematical models to incorporate population protective behaviors. Our retrospective prediction suggests that an increase of 100 daily new reported cases would lead to 6.60% (95% CI: 4.03, 9.17) more people worrying about being infected, increase 3.77% (95% CI: 2.46, 5.09) more people to avoid social gatherings, and reduce the weekly mean reproduction number by 0.32 (95% CI: 0.20, 0.44). Accordingly, the fourth wave would have been 14% (95% CI%: -53%, 81%) smaller if not for pandemic fatigue. This indicates the important role of mitigating pandemic fatigue in maintaining population protective behaviors for controlling COVID-19.

Assessing the longitudinal effects of the continuation and discontinuation of the school-located influenza vaccination programme on parental vaccine hesitancy in Hong Kong.

BACKGROUND: School-located influenza vaccination programme (SIVP) can effectively promote childhood seasonal influenza vaccination (SIV). However, the longitudinal effects of continuation and discontinuation of the SIVP on parents' vaccine hesitancy remained unknown. METHODS: A two-wave longitudinal study recruited adult parents who had at least one child attending a kindergarten or primary school using random-digital-dialled telephone interviews. Generalized estimating equation and structural equation modelling were used to examine the impact of changes in schools' SIVP participation status on parents' vaccine-related attitudes, and childhood SIV acceptance over 2 years in Hong Kong. RESULTS: Children's SIV uptake varied by the schools' SIVP participation status. The highest SIV uptake was found in schools that consistently participated in SIVP (Consistent participation group) (2018/2019: 85.0%; 2019/2020: 83.0%) but lowest in the Consistent non-Participation group (2018/2019: 45.0%; 2019/2020: 39.0%). SIV uptake increased in the Late Initiation group but declined in the Discontinuation group. An increasing trend of parental vaccine-hesitant attitudes was observed in the Consistent non-Participation group. CONCLUSIONS: Initiation and continuation of the SIVP can reduce parental vaccine hesitancy to achieve a high childhood SIV uptake. Conversely, discontinuation of the SIVP or persistent resistance to the implementation of SIVP can increase parental vaccine hesitancy and reduce childhood SIV uptake.

Effectiveness of CoronaVac and BNT162b2 Vaccines Against Severe Acute Respiratory Syndrome Coronavirus 2 Omicron BA.2 Infections in Hong Kong.

There is limited evidence on vaccine effectiveness against asymptomatic or mild Omicron infections. We estimated that recent third doses of messenger RNA or inactivated vaccines reduced the risk of self-reported infection by 52% (95% confidence interval, 17%-73%) among randomly sampled adults during the Omicron BA.2-dominated surge in Hong Kong.

Unveiling One-to-One Correspondence Between Excited Triplet States and Determinate Interactions by Temperature-Controllable Blue-Green-Yellow Afterglow.

Phosphorescence of organic materials is highly dependent on intermolecular interactions, for the sensitive triplet excitons toward environment and aggregated structures. However, until now, relationship between phosphorescence and intermolecular interactions is still unclear for complicated influence factors and uncontrollable aggregated behaviors. Herein, taking temperature as the controlled variable, the afterglow can continuously change from blue to green, then to yellow, even achieve the white emission with deuteration process. It is mainly due to the hierarchical architectures of molecular aggregates with rational distribution of intermolecular interactions, as well as gradually unlocking process of interactions with different energies. Accordingly, the one-to-one correspondence between the determinate interactions and excited triplet states have been established, guiding accurate design of desirable phosphorescence materials by hierarchical control of aggregated structures.

Universal Community Nucleic Acid Testing for Coronavirus Disease 2019 (COVID-19) in Hong Kong Reveals Insights Into Transmission Dynamics: A Cross-Sectional and Modeling Study.

BACKGROUND: Testing of an entire community has been used as an approach to control coronavirus disease 2019 (COVID-19). In Hong Kong, a universal community testing program (UCTP) was implemented at the fadeout phase of a community epidemic in July to September 2020. We described the utility of the UCTP in finding unrecognized infections and analyzed data from the UCTP and other sources to characterize transmission dynamics. METHODS: We described the characteristics of people participating in the UCTP and compared the clinical and epidemiological characteristics of COVID-19 cases detected by the UCTP versus those detected by clinical diagnosis and public health surveillance (CDPHS). We developed a Bayesian model to estimate the age-specific incidence of infection and the proportion of cases detected by CDPHS. RESULTS: In total, 1.77 million people, 24% of the Hong Kong population, participated in the UCTP from 1 to 14 September 2020. The UCTP identified 32 new infections (1.8 per 100000 samples tested), consisting of 29% of all local cases reported during the two-week UCTP period. Compared with the CDPHS, the UCTP detected a higher proportion of sporadic cases (62% vs 27%, P<.01) and identified 6 (out of 18) additional clusters during that period. We estimated that 27% (95% credible interval: 22%, 34%) of all infections were detected by the CDPHS in the third wave. CONCLUSIONS: We reported empirical evidence of the utility of population-wide COVID-19 testing in detecting unrecognized infections and clusters. Around three quarters of infections have not been identified through existing surveillance approaches including contact tracing.

Changing Disparities in Coronavirus Disease 2019 (COVID-19) Burden in the Ethnically Homogeneous Population of Hong Kong Through Pandemic Waves: An Observational Study.

BACKGROUND: Disparities were marked in previous pandemics, usually with higher attack rates reported for those in lower socioeconomic positions and for ethnic minorities. METHODS: We examined characteristics of laboratory-confirmed coronavirus disease 2019 (COVID-19) cases in Hong Kong, assessed associations between incidence and population-level characteristics at the level of small geographic areas, and evaluated relations between socioeconomics and work-from-home (WFH) arrangements. RESULTS: The largest source of COVID-19 importations switched from students studying overseas in the second wave to foreign domestic helpers in the third. The local cases were mostly individuals not in formal employment (retirees and homemakers) and production workers who were unable to WFH. For every 10% increase in the proportion of population employed as executives or professionals in a given geographic region, there was an 84% (95% confidence interval [CI], 1-97%) reduction in the incidence of COVID-19 during the third wave. In contrast, in the first 2 waves, the same was associated with 3.69 times (95% CI, 1.02-13.33) higher incidence. Executives and professionals were more likely to implement WFH and experienced frequent changes in WFH practice compared with production workers. CONCLUSIONS: Consistent findings on the reversed socioeconomic patterning of COVID-19 burden between infection waves in Hong Kong in both individual- and population-level analyses indicated that risks of infections may be related to occupations involving high exposure frequency and WFH flexibility. Contextual determinants should be taken into account in policy planning aiming at mitigating such disparities.

Assessing Community Vulnerability over 3 Waves of COVID-19 Pandemic, Hong Kong, China.

We constructed a coronavirus disease community vulnerability index using micro district-level socioeconomic and demographic data and analyzed its correlations with case counts across the 3 pandemic waves in Hong Kong, China. We found that districts with greater vulnerability reported more cases in the third wave when widespread community outbreaks occurred.

Barriers to preventive care utilization among Hong Kong community-dwelling older people and their views on using financial incentives to improve preventive care utilization.

BACKGROUND: Financial incentive is increasingly used as a mean to promote preventive care utilization (PCU), but the current Elderly Health Care Voucher Scheme (EHCVS) in Hong Kong is ineffective for encouraging PCU. OBJECTIVE: To explore the older people's barriers to PCU and their views on financial incentive, including EHCVS, for improving private PCU. DESIGN AND SETTING: Focus-group discussions were conducted in community elderly centres located in five districts of Hong Kong. PARTICIPANTS: Community-dwelling older people aged 60 years or above. RESULTS: Lack of understanding about preventive care and low awareness of the need for preventive care were key factors for the low motivation for PCU. Uncertainty over the level of service fee charged and concerns over service quality hindered the choice of using the private service providers under the current EHCVS. Financial incentives specific for preventive care services were thought to be cues to actions and guides for service promotion. However, some flexibility in service coverage and a set time limit of the financial incentives were preferred to accommodate individual needs. CONCLUSIONS: Apart from promoting knowledge of preventive care, official monitoring for service fee and quality is important for empowering older people to choose private service providers for preventive care. Financial incentives for preventive care services should be more specific to cue service promotion and uptake of preventive care while maintaining flexibility to accommodate individual needs. PATIENT OR PUBLIC CONTRIBUTION: Participants were recruited using purposive sampling with the coordination of community elderly centres. Data were analysed using thematic coding.

Measurement invariance across gender and age groups, validity and reliability of the Chinese version of the short-form supportive care needs survey questionnaire (SCNS-SF34).

BACKGROUND: Despite the wide use of the Short-Form Supportive Care Needs Survey Questionnaire (SCNS-SF34), the measurement invariance of the SCNS-SF34 across the main groups-gender and age-which might be of interest in the application of the instrument has never been confirmed. To provide an accurate assessment tool to evaluate the unmet needs of Chinese cancer patients, the present study aimed to assess the measurement invariance of the SCNS-SF34 across gender and age groups and to assess the validity and reliability of the Chinese version of the SCNS-SF34. METHODS: The SCNS-SF34 was administrated to 1106 Chinese cancer patients. Other instruments included the Memorial Symptom Assessment Scale-Short Form (MSAS-SF), the Short-Form-12 Health Survey version 2 (SF-12 v2) and the Hospital Anxiety and Depression Scale (HADS). Factor structure, internal construct validity, convergent validity, known-group validity and internal consistency were assessed. RESULTS: Our data fit the original five-factor model. Multi-group confirmatory factor analysis indicated measurement invariance across age and gender groups. The domains of the SCNS-SF34 had moderate correlations with the corresponding domains of the MSAS-SF, the SF-12 v2 and the HADS, which supported convergent validity. Of the 34 items, 33 had an item-total correlation that was corrected for an overlap of > 0.4 to support the internal construct validity. The SCNS-SF34 aptly differentiated patients by age and gender. The Cronbach's alpha coefficient ranged from 0.64 to 0.87. CONCLUSIONS: We confirm the measurement invariance of the Chinese version of the SCNS-SF34 across gender and age group. It is a valid and reliable tool for evaluating the needs of Chinese patients with cancer.

Public Engagement and Government Responsiveness in the Communications About COVID-19 During the Early Epidemic Stage in China: Infodemiology Study on Social Media Data.

BACKGROUND: Effective risk communication about the outbreak of a newly emerging infectious disease in the early stage is critical for managing public anxiety and promoting behavioral compliance. China has experienced the unprecedented epidemic of the coronavirus disease (COVID-19) in an era when social media has fundamentally transformed information production and consumption patterns. OBJECTIVE: This study examined public engagement and government responsiveness in the communications about COVID-19 during the early epidemic stage based on an analysis of data from Sina Weibo, a major social media platform in China. METHODS: Weibo data relevant to COVID-19 from December 1, 2019, to January 31, 2020, were retrieved. Engagement data (likes, comments, shares, and followers) of posts from government agency accounts were extracted to evaluate public engagement with government posts online. Content analyses were conducted for a random subset of 644 posts from personal accounts of individuals, and 273 posts from 10 relatively more active government agency accounts and the National Health Commission of China to identify major thematic contents in online discussions. Latent class analysis further explored main content patterns, and chi-square for trend examined how proportions of main content patterns changed by time within the study time frame. RESULTS: The public response to COVID-19 seemed to follow the spread of the disease and government actions but was earlier for Weibo than the government. Online users generally had low engagement with posts relevant to COVID-19 from government agency accounts. The common content patterns identified in personal and government posts included sharing epidemic situations; general knowledge of the new disease; and policies, guidelines, and official actions. However, personal posts were more likely to show empathy to affected people (χ21=13.3, P<.001), attribute blame to other individuals or government (χ21=28.9, P<.001), and express worry about the epidemic (χ21=32.1, P<.001), while government posts were more likely to share instrumental support (χ21=32.5, P<.001) and praise people or organizations (χ21=8.7, P=.003). As the epidemic evolved, sharing situation updates (for trend, χ21=19.7, P<.001) and policies, guidelines, and official actions (for trend, χ21=15.3, P<.001) became less frequent in personal posts but remained stable or increased significantly in government posts. Moreover, as the epidemic evolved, showing empathy and attributing blame (for trend, χ21=25.3, P<.001) became more frequent in personal posts, corresponding to a slight increase in sharing instrumental support, praising, and empathizing in government posts (for trend, χ21=9.0, P=.003). CONCLUSIONS: The government should closely monitor social media data to improve the timing of communications about an epidemic. As the epidemic evolves, merely sharing situation updates and policies may be insufficient to capture public interest in the messages. The government may adopt a more empathic communication style as more people are affected by the disease to address public concerns.

Effectiveness and Parental Acceptability of Social Networking Interventions for Promoting Seasonal Influenza Vaccination Among Young Children: Randomized Controlled Trial.

BACKGROUND: Seasonal influenza vaccination (SIV) coverage among young children remains low worldwide. Mobile social networking apps such as WhatsApp Messenger are promising tools for health interventions. OBJECTIVE: This was a preliminary study to test the effectiveness and parental acceptability of a social networking intervention that sends weekly vaccination reminders and encourages exchange of SIV-related views and experiences among mothers via WhatsApp discussion groups for promoting childhood SIV. The second objective was to examine the effect of introducing time pressure on mothers' decision making for childhood SIV for vaccination decision making. This was done using countdowns of the recommended vaccination timing. METHODS: Mothers of child(ren) aged 6 to 72 months were randomly allocated to control or to one of two social networking intervention groups receiving vaccination reminders with (SNI+TP) or without (SNI-TP) a time pressure component via WhatsApp discussion groups at a ratio of 5:2:2. All participants first completed a baseline assessment. Both the SNI-TP and SNI+TP groups subsequently received weekly vaccination reminders from October to December 2017 and participated in WhatsApp discussions about SIV moderated by a health professional. All participants completed a follow-up assessment from April to May 2018. RESULTS: A total of 84.9% (174/205), 71% (57/80), and 75% (60/80) who were allocated to the control, SNI-TP, and SNI+TP groups, respectively, completed the outcome assessment. The social networking intervention significantly promoted mothers' self-efficacy for taking children for SIV (SNI-TP: odds ratio [OR] 2.69 [1.07-6.79]; SNI+TP: OR 2.50 [1.13-5.55]), but did not result in significantly improved children's SIV uptake. Moreover, after adjusting for mothers' working status, introducing additional time pressure reduced the overall SIV uptake in children of working mothers (OR 0.27 [0.10-0.77]) but significantly increased the SIV uptake among children of mothers without a full-time job (OR 6.53 [1.87-22.82]). Most participants' WhatsApp posts were about sharing experience or views (226/434, 52.1%) of which 44.7% (101/226) were categorized as negative, such as their concerns over vaccine safety, side effects and effectiveness. Although participants shared predominantly negative experience or views about SIV at the beginning of the discussion, the moderator was able to encourage the discussion of more positive experience or views and more knowledge and information. Most intervention group participants indicated willingness to receive the same interventions (110/117, 94.0%) and recommend the interventions to other mothers (102/117, 87.2%) in future. CONCLUSIONS: Online information support can effectively promote mothers' self-efficacy for taking children for SIV but alone it may not sufficient to address maternal concerns over SIV to achieve a positive vaccination decision. However, the active involvement of health professionals in online discussions can shape positive discussions about vaccination. Time pressure on decision making interacts with maternal work status, facilitating vaccination uptake among mothers who may have more free time, but having the opposite effect among busier working mothers. TRIAL REGISTRATION: Hong Kong University Clinical Trials Registry HKUCTR-2250; https://tinyurl.com/vejv276.

Room-Temperature Phosphorescence Invoked Through Norbornyl-Driven Intermolecular Interaction Intensification with Anomalous Reversible Solid-State Photochromism.

Herein, norbornyl (NB), a bulky annular nonconjugated spacer, is melded into π systems to construct two groups of ladder-type room-temperature phosphorescence (RTP) luminogens. The effect of the NB on π-π interactions, packing modes and RTP performance is explored systematically. The experimental and computational results demonstrate the versatility of NB in reducing π-π distances and synergistically intensifying the intermolecular interactions, which not only induces intersystem crossing from S1 to Tn but also diminishes the nonradiative decay of triplet excitons. Impressively, 1800-fold phosphorescence lifetime enhancement is achieved in comparison with the reference compounds without NB. The molecular packing and RTP performance can be further modulated by the length of the backbones and terminal end-groups. It is quite peculiar that NB-annulated phthalic acid exhibits reversible photochromism in the solid state, likely due to the formation of persistent radical pairs. Our study paves an ingenious avenue towards enhancing intermolecular interactions and provides significant implications for a better comprehensive understanding of the origin of their RTP and the inherent photophysical mechanism.

9,9-Dimethylxanthene Derivatives with Room-Temperature Phosphorescence: Substituent Effects and Emissive Properties.

Room-temperature phosphorescence (RTP) emitters with ultralong lifetimes are emerging as attractive targets because of their potential applications in bioimaging, security, and other areas. But their development is limited by ambiguous mechanisms and poor understanding of the correlation of the molecular structure and RTP properties. Herein, different substituents on the 9,9-dimethylxanthene core (XCO) result in compounds with RTP lifetimes ranging from 52 to 601 ms, which are tunable by intermolecular interactions and molecular configurations. XCO-PiCl shows the most persistent RTP because of its reduced steric bulk and multiple sites of the 1-chloro-2-methylpropan-2-yl (PiCl) moiety for forming intermolecular interactions in the aggregated state. The substituent effects reported provide an efficient molecular design of organic RTP materials and establishes relationships among molecular structures, intermolecular interactions, and RTP properties.

Mechanoluminescence or Room-Temperature Phosphorescence: Molecular Packing-Dependent Emission Response.

Mechanoluminescence (ML) and room-temperature photophosphorescence (RTP) were achieved in polymorphisms of a triphenylamine derivative with ortho-substitution. This molecular packing-dependent emission afforded crucial information to deeply understand the intrinsic mechanism of different emission forms and the possible packing-function relationship. With the incorporation of solid-state 13 C NMR spectra of single crystals, as well as the analysis of crystal structures, the preferred packing modes for ML and/or RTP were investigated in detail, which can guide the reasonable design of organic molecules with special light-emission properties.

Bromine-Substituted Fluorene: Molecular Structure, Br-Br Interactions, Room-Temperature Phosphorescence, and Tricolor Triboluminescence.

Organic tribophosphorescence materials are rarely reported and the introduction of Br atoms may be a practical way to design such materials. Here four bromine-substituted fluorene-based derivatives are presented and BrFlu-CBr, having fluorescence-phosphorescence dual-emission induced not only by UV light but also by mechanical stimulus, manifests the highest phosphorescence efficiency of 4.56 % upon photoirradiation. During the grinding process, three different triboluminescent spectra were identified. Upon introduction of a mechanical stimulus, the triboluminescence emission is cyan, whereas after an extended period it changed to blue. After removing the mechanical stimulus, green-white phosphorescent emission was observed. Careful research on single-crystal structures and theoretical calculations demonstrate that strong Br⋅⋅⋅Br interactions are vital to facilitate spin-orbit coupling and promote intersystem crossing, thus generating the unique properties.

Avian influenza A/H7N9 risk perception, information trust and adoption of protective behaviours among poultry farmers in Jiangsu Province, China.

BACKGROUND: Poultry farmers are at high-risk from avian influenza A/H7N9 infection due to sustained occupational exposures to live poultry. This study examined factors associated with poultry farmers' adoption of personal protective behaviours (PPBs) based on Protection Motivation Theory (PMT). METHODS: Totally, 297 poultry farmers in three cities of Jiangsu Province, China were interviewed during November 2013-January 2014. Data on PMT constructs, perceived trustworthiness of A/H7N9 information from mass media (formal sources), friends and family (informal sources), intention to adopt and actual adoption of PPBs and respondents' demographics were collected. Structural equation modeling (SEM) identified associations between demographic factors and PMT constructs associated with A/H7N9-oriented PPB intention. Moderated mediation analysis examined how demographics moderated the effects of information trust on PPB intention via risk perceptions of A/H7N9. RESULTS: Respondents generally perceived low vulnerability to A/H7N9 infection. The SEM found that male respondents perceived lower severity of (ß = -0.23), and lower vulnerability to (ß = -0.15) A/H7N9 infection; age was positively associated with both perceived personal vulnerability to (ß = 0.21) and perceived self-efficacy (ß = 0.24) in controlling A/H7N9; education was positively associated with perceived response efficacy (ß = 0.40). Furthermore, perceived vulnerability (ß = 0.16), perceived self-efficacy (ß = 0.21) and response efficacy (ß = 0.67) were positively associated with intention to adopt PPBs against A/H7N9. More trust in informal information (TII) was only significantly associated with greater PPB intention through its positive association with perceived response efficacy. Age significantly moderated the associations of TII with perceived Self-efficacy and perceived response efficacy, with younger farmers who had greater TII perceiving lower self-efficacy but higher response efficacy. CONCLUSION: Poultry farmers perceive A/H7N9 as a personally-irrelevant risk. Interventions designed to enhance perceived response efficacy, particularly among lower educated respondents may effectively motivate adoption of PPBs. Informal information may be an important resource for enhancing response efficacy.

Healthcare seeking behavior of patients with influenza like illness: comparison of the summer and winter influenza epidemics.

BACKGROUND: Influenza often causes winter and summer epidemics in subtropical regions, but few studies have investigated the difference in healthcare seeking behavior of patients with influenza-like illness (ILI) between these two epidemics. METHODS: Household telephone surveys were conducted using random digit dialing in Hong Kong during July-August 2014 and March-April 2015. One adult from each household was interviewed for ILI symptoms and associated healthcare seeking behaviour of themselves and one child in the household (if any), during the preceding 30 days. Healthcare seeking behavior of respondents with self-reported ILI was compared between summer and winter influenza. Logistic regression was used to explore the factors associated with healthcare seeking behavior. RESULTS: Among 516 and 539 adult respondents in the summer and winter surveys, 22.6 and 38.0 % reported ILI symptoms, and 40.9 and 46.8 % of them sought medical care, respectively. There was no significant difference in healthcare seeking behavior between the summer and winter epidemics, except a higher proportion of self-medication in summer in the adult respondents. Among 155 and 182 children reported by the adults in both surveys, the proportion of self-reported ILI was 32.9 and 40.1 % in the summer and winter surveys, respectively. Of these children, 47.1 and 56.2 % were brought for medical consultation in summer and winter, respectively. Women, adults with diabetes and those with symptoms of cough, shortness of breath, and runny nose were more likely to seek medical consultations for ILI symptoms. The factors associated with seeking medical consultations in children with ILI symptoms included being female, age under 10 years, and with symptoms of sore throat or vomiting. Those older than 60 years were less likely to self-medicate, whereas regular smokers and those with symptom of sore throat were more likely to do so. CONCLUSION: Healthcare seeking behavior of the general public was not significantly different between these two epidemics. However ILI was associated with increased healthcare utilization in both winter and summer epidemics in Hong Kong.

Public risk perception and attitudes towards live poultry markets before and after their closure due to influenza A(H7N9), Hong Kong, January-February 2014.

BACKGROUND: The study investigated public risk perception regarding influenza A(H7N9) and attitudes towards closure of live poultry markets (LPMs) before and after LPMs closed in Hong Kong. METHODS: Two population-based surveys were conducted before and after LPMs closed in January-February 2014, respectively. Adults were recruited using random digital dialing. RESULTS: In total, 670 and 1011 respondents completed the survey before and after closure of LPMs, respectively. Perceived susceptibility to H7N9 infection was low across surveys. Among respondents who completed the survey after LPMs closed, only 14.6% agreed that temporary closure of LPMs caused inconvenience to the daily life; 38.7% valued the Chinese tradition of live poultry consumption more than controlling the risk of avian influenza; 54.6% recognized greater risk of influenza epidemic associated with LPMs. Support for permanent closure of LPMs which was comparably low across surveys was strongly associated with perceived risk of avian influenza related to LPMs, the effectiveness of LPM closure in control of avian influenza and the inconvenience caused by closure. CONCLUSIONS: Risk communication that promotes people's perceived risk of avian influenza associated with LPMs and the effectiveness of LPM closure in control of avian influenza outbreaks may improve support for permanent closure of LPMs.

Psychosocial Influences on Parental Decision-Making Regarding Vaccination Against Seasonal Influenza for Young Children in Hong Kong: a Longitudinal Study, 2012-2013.

PURPOSE: Vaccination uptake remained low, although annual subsidies are provided to encourage 6-72-month-old Hong Kong children to be vaccinated against seasonal influenza. This study was aimed to investigate the psychosocial influences on parental decision-making regarding young children's seasonal influenza vaccination. METHODS: One-thousand two-hundred twenty-six parents of eligible children were recruited using random digit dialing in August-October 2012 to assess baseline perceptions and re-contacted in March 2013 to record children's vaccination uptake. Structural equation modeling (SEM) was performed to examine factors associated with parental decision about children's vaccination based on the complete data of 1222 respondents. RESULTS: Of the 1226 respondents who completed the follow-up survey, 34.3 % reported that their child was vaccinated during the follow-up period. Child's past influenza vaccination history (ß = 0.48), belief in vaccination safety (ß = 0.35), and social norms (ß = 0.25) were strongly associated with parental intention to vaccinate their child which directly predicted child vaccination uptake (ß = 0.57). Belief in vaccination safety (ß = 0.42) and social norms (ß = 0.36) were strongly associated with vaccination intention of parents whose children never received influenza vaccine. CONCLUSION: Interventions that address concerns on vaccination safety and utilize social norms may be effective to initiate Chinese parents to vaccinate their children.