Participants in the current study will comprise Hong Kong Chinese older adults. Participants will be eligible if they are 65 years or over; retired or homemakers; willing to be randomly assigned to experimental or control groups; able to understand the study rationale; a first-language Cantonese-speaker; and, most importantly, non-vaccinated within 1 year and report never or rarely adopting any of the influenza prevention behaviors listed by the research group. Participants who report more frequent preventive behaviors will not be invited to attend the preliminary session. We will also exclude older adults who are dementia as well as who are fragile to move.
This project will be conducted in three phases over 24 months in a sample of older adults from Hong Kong. Phase 1 (Months 1 to 4) – Development of intervention using the HAPA theory and preparation for data collection including participant recruitment and preparation of materials and measures. Recruitment will overlap with Phase 2 until the required sample size has been recruited. Phase 2 (Months 4 to 20) – Implementation of the intervention including baseline measures, intervention administration through telephone, ongoing follow-up outcome (See Fig. 1). Phase 3 (Months 21 to 24) – Evaluation of intervention through: (a) evaluating the immediate impact through effects on outcomes at 6-month post-intervention; (b) evaluating the long-term impact of the intervention through effects on outcomes at 12-month follow up; and (c) assessing the compliance of the participants with the intervention.
Phase 1: intervention development
The rationale of the intervention development will be in developing increased motivation to adopt influenza preventive behaviors in Hong Kong older adults and assisting them in converting their motives into action and maintaining the behavior [16, 22]. According to the HAPA theory, motivation is a necessary but not sufficient condition for action initiation and persistence; people also need to identify effective plans to enact their intentions or motives. The protocol will therefore include intervention components that promote motivation (action self-efficacy, risk perception, and outcome expectancy) and planning (action and coping planning, maintenance and recovery self-efficacy).
Aims of the first phase are: (i) develop the content of the HAPA-based intervention to promote the influenza prevention behaviors of Hong Kong older adults building on our previous projects on influenza and influenza prevention; (ii) design an intervention training manual so that the intervention can be administered consistently across groups and replicated by others; (iii) develop the intervention delivery protocol consistent with the design of randomized controlled trial; (iv) develop measures of key outcome variables to be used to evaluate the effectiveness of the intervention; and (v) confirm participation of elderly centers (i.e., government-established elderly care facilities) to be involved in the intervention and secure ethical clearance for the study. Prior to the start of the project upon funded, the study protocol has been registered in CCRB Clinical Trials Registry of the Chinese University of Hong Kong, a Partner Registry of a WHO Primary Registry (Ref: CUHK_CCRB00567). Main components and example content of the study protocol are listed below.
Several motivational strategies of behavior initiation will be included: (a) The information-giving component will include a slide presentation from the facilitator to the group promoting the advantages, and negating the disadvantages, of influenza prevention for health and outlining the risk levels of influenza for older adults (targeting risk perception); a ‘how to’ education unit aimed at providing information about how to conduct influenza prevention behaviors in certain scenario, such as covering both mouth and nose when wearing facemasks instead of solely on month in a crowded place during peak of flu (targeting action self-efficacy); and a brief example of an influenza prevention program and possible outcomes and gains of engaging in regular influenza prevention behaviors (targeting positive outcome expectancy); (b) In the goal-setting exercise, participants will be given guidance on how to set a goal of adopting influenza prevention (targeting action self-efficacy). They will be told that the aim is to develop personal goals for increasing their influenza prevention behaviors, and participants will be encouraged to set goals realistic short- and long-term goals; (c) In the ‘mental simulation’ activity, participants will be asked to visualize the actions they would need to perform to achieve their goals and how they would feel once they had achieved those goals (targeting positive outcome expectancy); and (d) In the implementation intention activity participants will be asked to set specific action plans of when, where, and in which situations they will adopt influenza prevention behaviors and tying it in with everyday occurrences to remind them to implement their plan (targeting planning).
Several strategies will be introduced in the maintenance session and be compared with the concepts at the initiation session : (a) maintenance/relapse prevention self-efficacy instead of action self-efficacy, that is, building the confidence in overcoming barriers to continue the influenza prevention behaviors (e.g., avoiding embarrassment of wearing a facemask in a public place); (b) coping planning should be emphasized rather than simply focused on action planning, this is because that the established new behavior patterns might be threatened by previous habits and some specific situations; (c) the feelings of enjoyment/satisfaction in complying to the influenza prevention behaviors will be emphasized rather than the expectations of the benefits of influenza prevention behaviors, this because perceived satisfaction has long been demonstrated as a significant predictor of behavior maintenance; and (d) participants will be encouraged to actively seeking social support from their networks, which will replace the support from the project facilitator when the project is withdrawn.
Participants randomly assigned to the control group will not receive the behavior-change components of the telephone-delivered intervention sessions. Indeed, participants in the control group will receive some general information on influenza prevention in the group-delivered preliminary session. But, the behavior-change aspects of the information-giving component, goal-setting, mental-simulation, and implementation intention components will be absent from the control group as they will not receive the telephone-delivered intervention sessions. The part-time research assistants will be provided with training and a feedback session to ensure consistency in delivering the intervention.
Phase 2 – implementation of the intervention
We will assume a small effect size (Cohen’s d = .20) for the effect of the intervention in order to calculate a conservative post-intervention sample size sufficient to detect an effect. G*Power analysis using the between-factor (i.e., 3 groups) repeated measures (i.e., 4 phases; baseline, 3-month, 6-month, and 12-month measurements) multivariate analysis of variance (MANOVA) indicates that a sample size of 65 in each group is required at follow-up in order to detect a small effect size (d = .20) in the outcome variables with power (beta) set at .90 and significance level (alpha) set at .017 (i.e., .05/3). Based on conservative estimate of 25% attrition rates, we aim to recruit 261 participants at baseline (n = 87 participants per group).
Given the links the research team has established with the elderly centers (including District Elderly Community Centers, Neighborhood Elderly Centre) in our previous projects, we will make contacts (i.e., phones, emails, and faxes) with center-in-charges and employ their support in championing recruitment to the study. We plan to recruit participants who are registered as members of the elderly centers at the three main territories of Hong Kong (i.e., Hong Kong Island, Kowloon, and New Territories).
Preliminary group-based education session
Interested participants will be invited to attend an initial session where they will be screened for eligibility and be provided with full details of the study and an information and consent form pack. Participants will also be invited to participate in a one-off group education session on the general information about types of influenza, peak influenza season, routes of influenza transmission, and influenza preventive behaviors. Participants will then be randomized into one of the three conditions: (a) “behavior initiation” and (b) “behavior initiation + behavior maintenance”, and (c) “control group”. Randomisation will be conducted by a research staff who is blind to the composition of the participants using the online randomisation tool. Participants will be blinded to the intervention allocation, while the part-time research assistants will be blinded to the research purpose.
Participants will be asked to complete baseline demographic and psychological measures with the assistance of student helpers. Participants will be required to complete a questionnaire comprising: (a) demographic and economic variables (age, gender, education level, marital status and living arrangement, household income); (b) psychological variables using validated self-report measures of risk perception, outcome expectancies, action and coping self-efficacies, action and coping planning, and intention, with Chinese versions of these measures have been validated and used in a previous study , while items of recovery and maintenance self-efficacy  will be translated and back-translated and validated into Chinese prior to the start of study; and (c) influenza prevention behavioral variables (i.e., washing hands, avoid touching eyes, nose or mouth, and facemask wearing) will also be provided. In terms of the hand washing behavior, two situation-specific questions will be asked including (a) return to home and/or elderly center after being out and (b) before touching food. In terms of the behaviors of avoid touching eyes, nose or mouth, we ask how many times that participants be aware of and successfully inhibiting themselves touching their eyes, nose or mouth before they have washed their hands, particularly after they have been touching other objects that might lead them to exposure risk (e.g., stair rails and bannisters, door handles, chairs and tables, safety rails on the MTR etc.). In terms of the facemask wearing behaviors, we ask participants their facemask wearing behaviors when (a) in direct contact with people, (b) in crowded places such as shopping malls and the MTR. Participants will be informed that they will receive telephone calls in three randomly-selected days in the following 9 days asking them to report whether they have conducted the three influenza prevention behaviors. Participants’ self-reported clinical influenza episodes as well as flu-like symptoms during the past 3 months will also be collected.
Telephone-delivered individual behavior initiation sessions
Participants in (a) “behavior initiation” and (b) “behavior initiation + behavior maintenance” intervention groups will receive telephone-delivered intervention sessions at weekly intervals throughout the course of behavior initiation for 3 months. The purpose of these is to serve to remind participants of their influenza prevention goal and their action plans to implement them, mainly focused on the motivational stage. The intervention sessions will be administered by telephone lasting 10 to 20 min, and will be audio-recorded with the permission from participants for fidelity checks. To the extent that participants will have talked about their appropriate influenza prevention goals in the goal setting, mental simulation, and action planning exercises, step-by-step personal instructions and feelings about pursuing their goal, and when and where they will pursue their goals. Participants in the control group will not receive the telephone-delivered intervention sessions. Part-time research assistants will be recruited to deliver the telephone intervention sessions appropriately 10–15 min. They were be trained by, and receive feedback from, the PI and project coordinator and practice with each other in simulated scenarios.
Telephone-delivered individual behavior maintenance sessions
Following the behavior initiation session, all participants will be asked to report the three influenza prevention behaviors via telephone calls in three randomly-selected days in 9 days, clinical influenza episodes as well as flu-like symptoms in the past 3 months, and then they will again be invited to complete the same set of psychological outcome measures administered at baseline. Thereafter that only participants allocated to the “behavior initiation + behavior maintenance” intervention group will continue to receive telephone-delivered intervention sessions at weekly intervals for 3 months. The sessions will focus on strategies of behavior maintenance at the volitional stage.
At the 3-month (i.e., the middle time point of the intervention after the behavior initiation session), 6-month (post-intervention), and 12-month follow-up occasions, participants will receive the same set of psychological outcome measures administered at baseline. They will also be asked to report the three influenza prevention behaviors (i.e., washing hands, avoid touching eyes, nose or mouth, and facemask wearing) as well as whether they get vaccinated via telephone calls in three randomly-selected days in 9 days. Participants’ self-reported clinical influenza episodes as well as flu-like symptoms during the past 3 months will also be collected. Participants will be reminded of their follow-up visit by telephone in advance of their visit. In order to minimize attrition, in particular participants from the control group, a fixed amount of monetary reward will be provided to those who completed all assessments.
Phase 3 – evaluation of the intervention
We will include brief self-report measures at data collection sessions to gauge participants’ views of the acceptability of the intervention components and the intervention itself as well as measures of behavioral and psychological variables. This will provide useful data on the level of intrusion experienced by the participants and an indication of its acceptability. Questionnaire measures of planning will also provide evidence of compliance. In addition, we will conduct a content analysis of the scripts of the audio files recorded during the telephone-delivered intervention sessions, in order to confirm their compliance with the intervention. This will permit the formal evaluation of intervention fidelity. As part of the fidelity checks and to minimize the potential influence of contamination and spill-over, we will ask participants whether they are aware of any eligible participants from the other intervention or control groups are their friends they interacted with, whether they have enrolled in some influenza prevention classes offered by their centers, as well as whether they are aware of any special effort has been provided by the center to promote influenza prevention in the period of intervention. In addition, we will encourage participants not to share their experiences with other potential participants. Moreover, we will track the impact of the influence of the potential new pandemic if any by asking participants their awareness and feelings.
Psychological data will be collected at an isolated room provided by the elderly center during the baseline, the 3-month (the middle time point of intervention), the 6-month (post-intervention), and the 12-month follow-up occasions, whereas the three influenza prevention behaviors variables (i.e., washing hands, avoid touching eyes, nose or mouth, and facemask wearing) and vaccination will be collected via telephone calls in three randomly-selected days in nine. Participants’ self-reported clinical influenza episodes as well as flu-like symptoms during the past 3 months will also be collected.
Data will be stored in password-protected spreadsheets saved on a computer of a member of the research team. Data will be initially treated for missing values with multiple imputation. The distribution of the data will be examined that the skewed data will be log-transformed and replaced with median (interquartile range). All analyses will be conducted using full intention-to-treat analyses with scores on dependent variables for non-compliers carried over using the last-observation carried forward method. Independent samples t-tests and chi-square analysis will be used to test whether there are significant differences between non-compliers and compliers. We will analyze the effectiveness of the intervention using a series of linear mixed models on each behavioral and psychological outcome variable. In the analyses, four phases will be the within-participants factor and three intervention conditions will be the between-participants factor. Baseline scores for the dependent variables will be included as covariates in the analysis with salient demographic variables: age, gender, marital status, education level, and socioeconomic status. We will use Akaike and Bayesian information criteria to assess whether a compound symmetry covariance structure will provide the best model fit of each outcome variable. The phase (i.e., time of measurement) by intervention condition (i.e., behavior initiation + behavior maintenance; behavior initiation only; and control group) interaction will be the central test. Beyond main effects of the intervention, we will also test whether there are any statistically significant interactions between the intervention condition and the time factor. For all tests, the Cohen’s d effect size will be calculated associated with a 95% confidence interval. Structural equation modelling (SEM) will be used to test the hypothesized theoretical sequence in the HAPA model . In the analyses, the effect of the intervention group conditions will be included using a dummy coded variable along with the demographic and baseline variables. The 95% bias corrected (BC) bootstrapping method (with n = 5000 bootstrap resamples) was subsequently employed to test the indirect effects of mediators (e.g., intention, maintenance and recovery self-efficacy, action and coping planning) (25). The CONSORT Extension for Nonpharmacological Treatment Interventions will be followed to report the results.