A Voice-Annotated Digital Decision Aid to Promote Child Influenza Vaccination: A Feasibility Study

(1) Background: Child influenza vaccine uptake is suboptimal due partly to vaccine hesitancy. A voice-annotated digital decision aid, Flu Learning Object (FLO), was developed to facilitate parental decision-making. This study assessed parental views on FLO’s usability and utility and determined its preliminary effectiveness in increasing vaccine intention and uptake; (2) Methods: A single-center mixed method study was conducted in a public primary care clinic in Singapore. Parents of children aged 6 months to 5 years who were unvaccinated in the preceding year were recruited. In-depth interviews explored their views of using FLO. Pre- and post-FLO questionnaires assessed their vaccine intention and perceived usability using the System Usability Scale (SUS); (3) Results: 18 parents were recruited. They became more aware of benefits and potential complications, distinguished influenza from the common cold, and recognized recommendations by National Childhood Immunisation Schedule. FLO addressed parents’ concerns and supported their decision-making process. FLO has good usability with a mean SUS score of 79.3, ranked at approximately the 85th percentile. The usage of FLO significantly increased vaccine intention from 55.6% to 94.4% (p = 0.016) with an actual vaccine uptake rate of 50%; (4) Conclusions: Parents generally accepted FLO, which positively influenced their intention to vaccinate their child against influenza.


Introduction
Influenza is an acute respiratory infection (ARI) caused by influenza viruses which circulate worldwide [1]. Seasonal epidemics occur mainly during winter but may cause more irregular outbreaks throughout the year in tropical regions [1]. Among children under 5 years globally, there were an estimated 109.5 million influenza episodes in the year 2018 [2]. Influenza accounted for 5% of acute lower respiratory infection (ALRI) hospital admissions and 4% of in-hospital ALRI deaths with an estimated 35,000 total deaths from influenza-associated ALRI [2].
With such a high global burden of disease, the World Health Organization (WHO) recommends annual vaccination for children aged between 6 months to 5 years old as a preventive measure [1]. Centers for Disease Control and Prevention (CDC) estimated that influenza vaccination prevented 1.3 million illnesses, 866,000 medical visits, 9000 hospitalizations and 110 deaths among children under 5 years in the United States during the 2019-2020 influenza season [3]. Vaccination also reduced the odds of manifesting fever in breakthrough infections among children by 45% [4]. Despite such benefits of vaccinating children of this age group, the uptake rate is generally suboptimal, such as 44.4% in England and 66.7% in the United States during the 2021-2022 influenza season [5,6].
In tropical Singapore, ARI including influenza is the leading acute medical condition that presents to public primary care clinics, accounting for a quarter of a million attendances join the study via convenience sampling. Recruitment took place at the end of the child's clinic consultation or service including routine well-child and developmental screening visits. Written informed consent was then obtained from parents who agreed to complete the questionnaires and interview and have their child's medical records accessed. Each participant was assigned a unique study identification number to de-identify and ensure confidentiality. This study recruited participants who were at least 21 years old following Singapore's legal age of consent with no upper age limit. Parents who are not conversant in the English language were excluded as FLO is delivered in English. Those whose children have received influenza vaccines in the preceding year were also excluded as current vaccine intention and uptake were less likely given the recent uptake. This study did not exclude any participant whose child had previously experienced any vaccination-related adverse event, including allergies, as influenza vaccination may not be contraindicated.

Data Collection
The participants attended a single study session conducted via an online video conferencing platform or face-to-face at a suitable date and time as per their individual availability and convenience. Prior to using FLO, parents completed an online questionnaire (Appendix A) that collected their sociodemographic data and assessed their vaccine intention on a 5-point Likert scale (1 = definitely will not vaccinate; 2 = likely will not vaccinate; 3 = undecided; 4 = likely will vaccinate; 5 = definitely will vaccinate). After using FLO, parents completed a second questionnaire (Appendix B) that reassessed their vaccine intention and evaluated parents' perceived usability of FLO based on the 10-item System Usability Scale (SUS) [29]. SUS was selected as the tool for assessing usability as it is highly valid, reliable and quick to administer [30]. Alternating positive and negative statements in SUS also minimizes extreme response and acquiescence biases [30]. A tool's usability is considered good when its SUS score corresponds to a rank of at least the 70th percentile [31]. Both the pre-and post-FLO questionnaires were administered using FormSG, which is an end-to-end encrypted online form builder used by Singapore's public healthcare clusters and government agencies for capturing classified data [32].
In-depth interviews were conducted during the same study session to collect qualitative data on parental views on the usability and utility of FLO. A topic guide (Appendix C) was developed and pilot-tested for reference during the interviews. Each interview lasted between 10 and 30 min and was audio recorded and later transcribed by the study team. The respective children's medical records on Sunrise Clinical Manager (the electronic medical record system used by SingHealth Polyclinics) were reviewed three months after the study session to determine if there was any actual vaccine uptake after parents used FLO. The participants were remunerated with an SGD20 (approximately USD15) grocery voucher each for their time and contribution to the study.

Data Analysis
Quantitative data were analyzed using IBM ® SPSS ® Statistics version 27. Participants' responses on the SUS were analyzed with their sociodemographic variables using a t-test, analysis of variance (ANOVA) test and Fisher's exact test. Pre-and post-FLO intention to vaccinate were compared using the McNemar test.
A framework analysis approach was deployed to identify emerging themes. A coding framework was developed to analyze the qualitative data. After auditing interview transcripts for accuracy, three authors (SYG, ASM, NCT) independently read through the initial three transcripts to closely familiarize themselves with the data. The authors then independently generated a list of initial codes by applying line-by-line coding of the transcripts. Coding discrepancies were resolved via discussion and consensus. Subsequent transcripts were coded by SYG and indexed using NVivo™ version 12 Plus (QSR International). The authors regularly discussed the qualitative data and the codes. SYG interpreted the codes by identifying characteristics and differences between the codes to label the emerging subthemes. Subsequently, the study team reviewed, revised, refined and named the final subthemes. The analysis was undertaken concurrently with data collection to check for data saturation, which was achieved when no new codes emerged and were confirmed by the final three transcripts [33]. through the initial three transcripts to closely familiarize themselves with the data. The authors then independently generated a list of initial codes by applying line-by-line coding of the transcripts. Coding discrepancies were resolved via discussion and consensus. Subsequent transcripts were coded by SYG and indexed using NVivo TM version 12 Plus (QSR International). The authors regularly discussed the qualitative data and the codes. SYG interpreted the codes by identifying characteristics and differences between the codes to label the emerging subthemes. Subsequently, the study team reviewed, revised, refined and named the final subthemes. The analysis was undertaken concurrently with data collection to check for data saturation, which was achieved when no new codes emerged and were confirmed by the final three transcripts [33].

Characteristics of Participants
Participants' sociodemographic characteristics are reported in Table 1.

Usability of FLO on the System Usability Scale (SUS)
Participants' perceived usability of FLO was assessed based on the 10-item System Usability Scale (SUS). FLO has a mean score of 79.3 on the SUS, ranked at approximately 85th percentile, thus showing good usability as demonstrated in Figure 2 [31].
Participants' responses on the SUS were analyzed with their sociodemographic variables using a t-test, an analysis of variance (ANOVA) test and Fisher's exact test. Within each sociodemographic characteristic category (age, sex, race, highest education level, combined monthly parental income), there is no significant difference in the SUS scores reported (all p-values exceed 0.05).

Main Qualitative Findings
The themes and subthemes identified from in-depth interviews with participants are summarized in Table 2.

Themes
Description of Themes Subthemes

Main Qualitative Findings
The themes and subthemes identified from in-depth interviews with participants are summarized in Table 2. FLO's narrative is generally straightforward with the language used being easy to understand and the fonts used being visibly clear.
"My English is not really good but the terms they use there are really easy to understand." P2 (Mother of 2-year-and-1-month-old boy) "It's very educational. And it's very simplified. Easy to understand because it summarized the whole thing. The words (are) also clearly mentioned. It's quite big and easy to capture because it's all mainly in black. . . . So, it catches my attention." P9 (Mother of 7-monthold girl) A few of the participants felt that the addition of keywords, headers and subtitles may be helpful.
"I would think that if there are just keywords, it will help me remember better. Maybe just one word of each picture to describe the process. Maybe something like, sort of like "vaccine", "virus", "immunity"." P14 (Mother of 6.5-month-old girl) "I think subtitles would be helpful too." P6 (Father of 6-month-old boy)

Images and Animation Aid Understanding
The illustrations used in FLO aided in parents' understanding of its contents.
"I think it was quite well-drawn, the animation images and ya, quite appealing for people to see. I think one of the images that I remember quite clearly was the "A B C" that was talking about school, missing school for children. So, I think when you put this information into images, it does help convey the messages across quite clearly." P17 (Mother of 6-month-old girl) "Like with the pie chart, I mean it shows twenty-five percent is substantial so I think that's easy to understand . . . I think the use of pictures more than words is great because that will cut through language barriers or age barriers, things like that. And it's just, you know, easier to digest with pictures." P20 (Mother of 6-month-old boy) Several parents opined that professional rendering, localized features and improving transition motion may enhance FLO further.
"I think the features of the visual cues were sometimes a little bit more like Western as compared to like having more Asian kind of features and looks. So, I think maybe just contextualizing it to a more local population might be . . . So, it's a little bit more relatable." P8 (Mother of 6-month-old boy) "Some way of differentiating each section. Headers will be useful. Colour differences or some animation differences. Maybe the background can be a different colour. So it's a bit, like a transit to a different topic, subtopic." P17 (Mother of 6-month-old girl) Monotonous and Foreign-Sounding Narrator Can Be Improved The narrator's voice is monotonous and foreign, which could potentially be improved by using a more pleasant and locally accented narration.
"The voice of that narrator is too monotonous. It doesn't come across as a voice that you trust." P3 (Father of 1-year-and-6-month-old girl) "I found the voice-over a little bit unfamiliar, just because of the accent. I'm not sure whether the local population would take to it very well. . . . I usually think that female voices are a little bit more pleasant." P8 (Mother of 6-month-old boy) Duration Is Acceptable Parents generally found FLO's duration to be acceptable.
"The duration (is) also quite nice, right? It's like three minutes is good." P1 (Father of 2-year-and-8-month-old boy) "Because we are very fast nowadays, we need a short and simple and very understandable message. For a short period of time, everything is compact and all the information is there." P10 (Mother of 1-year-and-7-month-old boy)

Utility Gain Understanding of Influenza and Its Effects
The participants became aware of the possible severe effects of influenza and how it differs from the common cold.
"It may cause death . . . wah it's (a) shocking thing for me" P9 (Mother of 7-monthold girl) "I think what was really great also was that the video helped me understand the difference between flu and the common cold, which I think is very commonly associated with one another and people think is the same thing." P6 (Father of 6-month-old boy)

Raises Awareness of Child Influenza Vaccine
Several participants were unaware of the child influenza vaccine prior to using FLO. then (I) will take off (work) so it will (be) quite a trouble to me. But if you get the vaccine then you might get a milder symptom right. So, the symptoms won't get so worse until I cannot send my kid to the care centre. So, this is something that I want to avoid. It's very difficult for the parents right. If both are working parents, so, it's tough for us to take one week off without proper planning." P18 (Father of 6-month-old boy) "(I'm) Scared they will pass it to others, other children in school or will pass (it) to their grandparents." P11 (Mother of 1-year-and-6-month-old girl) Potential Vaccine Side Effects Are Acceptable Many parents concurred that vaccine side effects were their main concern but were reassured by the information presented by FLO.
"(FLO) addressed the part on side effects, which I think is very rare (ly mentioned elsewhere). A lot of parents are concerned about side effects. It helps when people know that there's some mention about side effects from the vaccination." P4 (Father of 4-year-and-9-month-old girl) "I see clearly that the side effects are not a big deal for my child but the effect when he gets the flu will be more serious." P2 (Mother of 2-year-and-1-month-old boy)

Informs Recommendations by National Childhood Immunisation Schedule (NCIS)
Parents recognized vaccine recommendations in the NCIS along with its financial subsidy, which are motivating factors that encouraged vaccine intention.
"If it is part of the flow of the vaccination that is recommended, then, yes, I would bring her for it." P14 (Mother of 6.5-month-old girl) "This is fully subsidized by (the) government. It's more encouraging for the people to take. Because some people (are) concerned about the finances. So when they know this is actually fully subsidized by the government, they would love to take for their child's safety." P10 (Mother of 1-year-and-7-month-old boy)

Desire Information on Vaccination Frequency and Access
The participants wanted FLO to include information about vaccination frequency and where they can get the vaccine.
"I understand in adults, it needs to be taken frequently, so several times, maybe twice a year, if I'm not wrong. So then, I would have a similar question whether that was the case for children also. . . . How can I register my child for the flu vaccine or how can I get it?" P17 (Mother of 6-month-old girl) "I would have liked to know more about the seasons, in terms of like how often I need to get the flu vaccine, or how long it would last and things like that. And then like do I just go to the polyclinic to request for it?" P19 (Mother of 6.5-month-old boy)

Decision-Making Statistics Quoted Are Useful
Statistics quoted by FLO aided parents in their decision-making process. "What I want to know like after the injection (side effects) . . . Actually it's more for her health. At the same time the subsidy that actually (makes me) want to go for this injection." P12 (Mother of 4-year-and-2-month-old girl) "Think it's the second or third last slide where it lists out, okay, you need to decide based on your child's health. Think about impact to child's health, to other loved ones, financial costs, school or work, et cetera. So that, even if you're thinking, "okay no", why don't you rethink in terms of these aspects, you know, if you're willing to have them all impacted. I think that is a good reminder to people who maybe think, "okay, maybe I can just risk it, like I don't need to get vaccinated for every disease out there"." P20 (Mother of 6-month-old boy)

Implementation Implementation Proposals
Parents proposed various suggestions on the ideal timing and setting to view FLO. Suggested timings included before compulsory vaccinations, antenatal and from birth. Suggested settings included clinic, home and school or childcare orientation.
"I guess maybe at the point when they bring their child for vaccination. . . . When they're waiting. Then if the flu (vaccine) is going to be offered to them at the same setting, then they can make a better decision. . . . Via iPad or maybe on, just on the TV. . . . So, if it's shown there in the waiting area, I guess it might encourage some parents and maybe myself to do it at the same setting." P19 (Mother of 6.5-month-old boy) "My husband (does) not really support that we should take the vaccines when baby (is) just born. He thinks the baby needs (to grow) big a bit (and) then the brain, the body will develop enough to take the vaccine. He thinks we can just delay the flu vaccine since Singapore is very clean. So, I think it should start from birth then the parents get enough time to make decision. This is a big deal for some parents." P2 (Mother of 2-year-and-1-month-old boy) "There is orientation for school. I think schools need to actually promote this video. So when the parents know about this thing, they will love to subscribe it for their child. Cause most of the parents are very busy and (have) no time . . . They invite parents for the first time (to) go to school, so, parents will know that "oh there's such thing". I don't think a lot of parents out there know about this flu jab." P10 (Mother of 1-year-and-7month-old boy)

Vaccine Intention and Uptake
The participants chose either option 3 (undecided), 4 (likely will vaccinate) or 5 (definitely will vaccinate) on a 5-point Likert scale that assessed their vaccine intention. No participants chose option 1 (definitely will not vaccinate) or 2 (likely will not vaccinate). Those who chose either option 4 or 5 were deemed to have a positive intention to vaccinate. The usage of FLO significantly increased vaccine intention from 55.6% to 94.4% (p = 0.016) as demonstrated in Figure 3.
A review of the children's medical records three months after the study session indicated an actual vaccine uptake in 50% of children after their parents used FLO (Figure 1). Briefly, 30% of the parents who indicated positive vaccine intention both before and after using FLO did not vaccinate their children in the end. The only parent who remained undecided even after using FLO, however, ended up vaccinating her child.
The participants chose either option 3 (undecided), 4 (likely will vaccinate) or 5 (definitely will vaccinate) on a 5-point Likert scale that assessed their vaccine intention. No participants chose option 1 (definitely will not vaccinate) or 2 (likely will not vaccinate). Those who chose either option 4 or 5 were deemed to have a positive intention to vaccinate. The usage of FLO significantly increased vaccine intention from 55.6% to 94.4% (p = 0.016) as demonstrated in Figure 3. A review of the children's medical records three months after the study session indicated an actual vaccine uptake in 50% of children after their parents used FLO ( Figure  1). Briefly, 30% of the parents who indicated positive vaccine intention both before and after using FLO did not vaccinate their children in the end. The only parent who remained undecided even after using FLO, however, ended up vaccinating her child.

Discussion
Parents generally accepted the FLO prototype, which had significantly influenced their intention to vaccinate their child against influenza. Various design features such as comprehensible language, relevant visual aids, pertinent statistics, and short video duration made FLO highly usable. FLO was useful in addressing parental concerns regarding child influenza vaccination. The participants realized how vaccination could protect their children and other loved ones against the potential severe consequences of influenza while minimizing taking time off work or school. Parents considered the potential vaccine side effects to be acceptable in comparison. Recognizing that the National Childhood Immunisation Schedule (NCIS) recommends and subsidizes the vaccine was also a key motivating factor in encouraging vaccine intention.
Whereas most parents indicated positive vaccine intention after using FLO, only half demonstrated actual uptake. The actual vaccine uptake rate of 50% still remains far higher than the nationwide rate of 7.6% [11,12]. Although, Singapore has not specified any vaccine uptake rate target, the National Health Service (NHS) of England aimed for at least a 50% vaccine uptake in preschool-aged children [13].
Several possible reasons may account for the discrepancy between vaccine intention and actual uptake rates. The medical records reviewed were only for visits to SingHealth

Discussion
Parents generally accepted the FLO prototype, which had significantly influenced their intention to vaccinate their child against influenza. Various design features such as comprehensible language, relevant visual aids, pertinent statistics, and short video duration made FLO highly usable. FLO was useful in addressing parental concerns regarding child influenza vaccination. The participants realized how vaccination could protect their children and other loved ones against the potential severe consequences of influenza while minimizing taking time off work or school. Parents considered the potential vaccine side effects to be acceptable in comparison. Recognizing that the National Childhood Immunisation Schedule (NCIS) recommends and subsidizes the vaccine was also a key motivating factor in encouraging vaccine intention.
Whereas most parents indicated positive vaccine intention after using FLO, only half demonstrated actual uptake. The actual vaccine uptake rate of 50% still remains far higher than the nationwide rate of 7.6% [11,12]. Although, Singapore has not specified any vaccine uptake rate target, the National Health Service (NHS) of England aimed for at least a 50% vaccine uptake in preschool-aged children [13].
Several possible reasons may account for the discrepancy between vaccine intention and actual uptake rates. The medical records reviewed were only for visits to SingHealth Polyclinics. Children who may have received influenza vaccination in other non-SingHealth polyclinics, general practitioner's clinics or pediatrician's clinics would not have their vaccination counted for the purpose of this study. A review of the National Electronic Health Record (NEHR) which included National Immunisation Registry (NIR) records would have provided a more accurate finding; however, the Ministry of Health of Singapore had previously precluded using NEHR for research purposes and determined its usage solely for clinical care only. The timing of the child's next medical appointment could be another limiting factor. Some of these appointments are well beyond three months from the time of the study session, and parents may potentially opt for convenience in timing their child's influenza vaccination to coincide with the next medical appointment. Parents may also choose to postpone influenza vaccination so as not to coincide with other childhood vaccinations. Multiple studies have shown that a common barrier to vaccination is having multiple injections during a single visit [34][35][36]. Most parents prefer having no more than two injections per visit due to concerns such as child's pain and discomfort, compounded vaccination adverse effects, and excessive load on the child's immune system [34][35][36]. Parents' acceptance towards receiving more than two injections per visit significantly increases as the child grows older [34]. A longer study duration can perhaps demonstrate if vaccination timings similarly influence actual vaccine uptake amongst study participants.
This study was also conducted in the midst of the COVID-19 pandemic whereby COVID-19 vaccination was available for older children. Discussions were underway of possible vaccination for younger children aged under 5 years old, which is the same age group of the child population of this study. This might perhaps limit parents in vaccinating their children against influenza as they prioritized possible COVID-19 vaccination with dose interval timing considerations.
Ensuring vaccine availability is another important facilitator to vaccine uptake with a lack of access due to vaccine shortage being a barrier [37,38]. Local practices include ordering vaccines in batches to avoid wastage. Parents may intend to vaccinate their child but may not have actual uptake if the vaccine is currently out of stock. Potential strategies to curb the issue include accurate calculations to project vaccine quantity required and implementing an effective vaccine appointment scheduling system.
To the best of the authors' knowledge, this is the first study in Singapore that evaluates the use of a decision aid on childhood influenza vaccination. The strength of this study lies in its mixed methods approach. Quantitative data on System Usability Scale (SUS) scores is further enriched by contextualized qualitative insights provided by parents during in-depth interviews. A preliminary assessment on FLO's effectiveness in increasing vaccine intention and uptake also provides an exploratory outlook on its application in actual clinical practice.
FLO is also delivered in English to match the target population's demographic characteristics. English is the primary language for education and all official communications in Singapore. Nationwide across all ages, the literacy rate is high at 97.1% with 74.3% possessing multi-language literacy and 48.3% speaking English as their primary language at home [39]. In total, 80-90% of those aged between 25 to 50 years old (the typical age range of parents with children under 5 years old) have also attained post-secondary or higher academic qualifications [39]. This is similarly reflected by the highest education level achieved by this study's participants with the majority possessing university degrees.
The discussion of child influenza vaccination using FLO may likewise encourage discussion and decisions on other childhood vaccinations as parents may have similar concerns for these other vaccines as well. A case for illustration is this study's P2 who is the mother of a 2-year-and-1-month-old boy who has not received any form of vaccination since birth including those that were mandatory prior to starting formal schooling. The usage of FLO has enabled P2 to better appreciate the importance of vaccines in preventing the severe consequences of communicable diseases and empowered her discussions with her husband. This contributed to P2 s son eventually receiving not only the influenza vaccine but also catching up on all the other childhood vaccines recommended by the NCIS.
This study has its limitations. As discussed earlier, vaccinations performed outside of SingHealth Polyclinics or beyond three months after the study session were not captured. Being a pilot study, its findings cannot be generalized. The participants' suggestions on further improving the animation features and the narrator's voice will be considered in further enhancing FLO. Future studies with an adequately powered sample size can assess if the enhanced FLO remains acceptable to parents and increase their vaccine intention with eventual uptake.
Challenges in adopting and implementing the enhanced FLO in routine clinical practice may include a lack of shared decision-making culture, time constraints and impact on healthcare providers' workload [40,41]. The adequate training of healthcare providers and systematizing the delivery of FLO to the target population prior to decision-making visits may contribute to successful adoption and implementation [40,41]. The digital nature of FLO can aid such systematic delivery in line with several implementation proposals suggested by participants. Providing an appointment-booking link at the end of FLO can promote vaccine uptake. Linking the measurements of FLO's usage with the intended outcome data of the vaccine uptake rate can further align key organizational priorities for sustainable integration into routine care [41].

Conclusions
FLO demonstrates good usability with its high SUS rank of the 85th percentile. The information gained from FLO was helpful in addressing parental concerns about child influenza vaccination and in supporting their decision-making process. The usage of FLO has also significantly increased parental intention in vaccinating their child against influenza from 55.6% to 94.4% with an actual vaccine uptake rate of 50%. The further enhancement of FLO coupled with systematic delivery can contribute to successful implementation in routine care to further improve vaccine uptake.  Secondary school c.
University-bachelor's degree e.
Combined monthly parental income (rounded up to nearest dollar): a. ≤SGD5000 b.

7.
Where do you usually prefer to bring your child to for his/her vaccinations?
a. Polyclinic b.
Have you ever vaccinated your child against influenza?
a. Never b.
Some years c.
Every year 9. Are you aware that child influenza vaccination is recommended by the National Childhood Immunisation Schedule (NCIS)?
a. Yes b. No 10. How likely will you be vaccinating your child against influenza this year?
a. 1-Definitely will not vaccinate b.
2-Likely will not vaccinate c.