Abstract
Objectives:
To assess knowledge, attitudes, and practices (KAP) towards herpes zoster (HZ) and HZ vaccination in Japan.
Methods:
This mixed-methods study was conducted across two phases. In Phase 1, concept elicitation interviews were conducted with the public (N = 24) and physicians (N = 6), and the Capability-Opportunity-Motivation-Behavior model of behavioral change was used to identify themes surrounding KAP. These themes were validated in Phase 2 via self-administered quantitative surveys conducted with a larger group of respondents (public: N = 600; physicians: N = 60).
Results:
Despite high awareness of HZ (92.9%–94.0%) and HZ vaccination (76.0%–80.4%) among the public, knowledge about HZ, HZ vaccination rates (13.1%–32.0%), and intention to vaccinate (12.6%–18.2% among non-HZ-vaccinated respondents) were low. Public respondents were likely to vaccinate against HZ upon physician recommendation (78.7%–84.0%), but physician recommendation was limited by barriers including perceived low patient willingness (51.7%) and vaccine cost (51.7%). Various forms of government support could encourage patient-physician discussions regarding HZ and aid HZ vaccination uptake among the public (30.0%–53.3%).
Conclusion:
These findings may inform public health strategies to overcome barriers to HZ vaccine uptake in Japan.
Introduction
Herpes zoster (HZ) is a viral disease caused by reactivation of latent varicella zoster virus in the dorsal root ganglia [1, 2]. Characterized by a painful dermatomal rash [1, 2], HZ can cause debilitating long-term complications including postherpetic neuralgia (PHN; i.e., pain persisting for >90 days post-rash onset), vision loss, and long-lasting motor deficits [3, 4]. HZ has substantial impact on quality-of-life (QoL), including physical, social, and emotional functioning [4, 5].
The risk of developing HZ increases with age, especially after 50 years, due to age-related decline in immunity [4]. Certain comorbidities with increased prevalence in older adults, including diabetes and cardiovascular diseases [6, 7], have also been associated with elevated HZ risk [8–10]. There is thus concern about HZ burden increasing in ageing populations such as Japan [11], where HZ incidence is highest in adults aged ≥50 years [1].
While HZ is generally treated with antiviral drugs and analgesics [12], these have demonstrated limited efficacy against PHN and minimal impact on QoL [4, 13–15]. Conversely, HZ vaccination (a proactive approach to HZ prevention) may reduce HZ risk and mitigate the severity and impact of HZ symptoms [16–18]. Two HZ vaccines are currently available in Japan: freeze-dried live attenuated varicella vaccine [19, 20] and recombinant zoster vaccine (RZV) [21–23]. Both are approved for HZ prevention in adults aged ≥50 years, and RZV additionally in adults aged ≥18 years at increased HZ risk.
HZ vaccination was recently added to Japan’s National Immunization Program (NIP) for adults aged 65 years and those aged 60–64 years with weakened immunity due to human immunodeficiency virus (HIV) infection [24]. However, Japan’s long-standing history of vaccine hesitancy may hinder vaccine uptake; with major safety concerns raised by Japanese citizens and health ministry regarding a range of vaccines in the past, vaccine confidence in Japan is one of the lowest worldwide [25, 26].
To date, limited studies have described knowledge, attitudes, and practices (KAP) towards HZ and HZ vaccination among adults aged ≥50 years in Japan [15], suggesting an under-recognition of HZ burden and the importance of HZ prevention. Alongside factors influencing HZ vaccination at an individual level, effective communications with healthcare professionals (HCPs) are also crucial in improving public knowledge about health issues and influencing vaccine-seeking behaviors [27, 28]. A useful framework for identifying drivers of HZ vaccination is the Capability-Opportunity-Motivation-Behavior (COM-B) model of behavioral change (Supplementary Figure S1). Commonly used to design and evaluate behavioral change interventions and policies, the model posits that behavioral change arises from targeting the interinfluencing components of capability, opportunity, and motivation [29].
This study therefore sought to use the COM-B model to assess KAP towards HZ and HZ vaccination among the public and physicians in Japan, and explore differences in KAP across different respondent subgroups; these insights may inform local public health interventions surrounding HZ prevention. This is an extension of a previous Asia-Pacific regional study involving Hong Kong, Republic of Korea, Singapore, and Taiwan, which identified knowledge gaps and cognitive biases that could be addressed to improve HZ-related practices in the region [30].
Methods
Study Design
A mixed-methods study was conducted across two phases with Japanese respondents (Supplementary Figure S2). In Phase 1, exploratory, concept elicitation, one-to-one virtual interviews (∼45 min) were conducted in Japanese with the public and physicians in January–March 2023. An interview discussion guide was developed based on a literature review of KAP regarding HZ and HZ vaccination, and discussions with a local expert engaged to provide expert opinions on study material. Relevant themes surrounding KAP related to HZ and HZ vaccination were summarized from the interview responses, using the COM-B model to identify behavioral gaps or barriers [29]. Further details on the Phase 1 study design and data analysis were previously published [30].
The themes identified in Phase 1 were quantitatively validated in Phase 2, which involved a self-administered cross-sectional survey (∼30 min) conducted with a larger group of respondents in April–May 2023. The survey questionnaire was designed based on themes elicited in Phase 1, which were categorized into COM-B domains centered around topics including knowledge, motivations, and opportunity, capturing attitudes and behaviors towards HZ and HZ vaccines (Supplementary Appendix S1, S2); the literature review and expert input were also considered. The questionnaire was then translated into Japanese and completed by all respondents online. Descriptive analyses of all questions were conducted according to respondent groups and subgroups, and presented as counts, percentages, means, and standard deviations depending on the scale of the item/measure. Bivariate comparisons between different respondent groups and subgroups were also conducted (Pearson’s Chi Square tests and one-way analyses of variance [ANOVA] for categorical and continuous variables, respectively).
A protocol amendment to the prior approved regional study was submitted to the above-country central Institutional Review Board (IRB), Pearl IRB, to include Japan as a participating country; exemption from full review was obtained (#21-CERN-104). A statement of informed consent was provided to all potential respondents who met eligibility criteria. Informed consent was obtained electronically for both phases.
Study Population
The study was conducted with public (i.e., non-physician) and physician respondents in Japan. Based on previously published mixed-methods studies (not HZ-related) [31–33], a sample size of 24–30 public respondents in Phase 1 was considered sufficient to identify significant themes for validation in Phase 2. Similarly, based on previously published studies in HZ [34–36], a sample size of 450–600 public respondents in Phase 2 was recommended; sample sizes of public respondent subgroups and physicians were estimated based on feasibility of recruitment.
In both phases, public respondents were recruited via Kantar Profiles panel and/or its partners’ databases through purposive sampling. Potential respondents were screened for eligibility, via phone calls/emails (Phase 1) or an online screener (Phase 2), based on the prespecified inclusion and exclusion criteria (Supplementary Table S1). Subgroups of public respondents were recruited: (i) HZ-naïve adults aged ≥50 years, (ii) adults aged ≥50 years, vaccinated with zoster vaccine live or RZV, (iii) current or former HZ patients aged ≥50 years, and (iv) working/financially independent adults aged 30–49 years, with parents aged ≥50 years. The (iv) group was included due to the important role children often play in healthcare decision-making and financial support for their elderly parents in Asian societies [37].
Physician respondents were recruited through purposive sampling via HCP databases consolidated from hospital websites and public HCP registries in Japan. General practitioners (GPs), pain clinicians, and dermatologists were recruited, based on the prespecified eligibility criteria (Supplementary Table S1).
Respondents who participated in the initial concept elicitation interviews (Phase 1) were excluded from the online quantitative surveys (Phase 2).
Results
Phase 1 (Concept Elicitation)
Demographics
A total of 24 members of the public and 6 physicians were interviewed. Public respondents included 6 non-HZ-vaccinated adults aged ≥50 years, 6 HZ-vaccinated adults aged ≥50 years, 6 current or former HZ patients aged ≥50 years, and 6 working/financially independent adults aged 30–49 years with parents aged ≥50 years (hereafter described as “adult children”). Of all adults aged ≥50 years (hereafter described as “older adults”), half were aged ≥65 years. Physician respondents included 2 GPs, 2 pain clinicians, and 2 dermatologists.
The Public
Public respondents reported some awareness of HZ based on experiences shared by HZ-experienced family/friends and media coverage. Current knowledge of HZ symptoms, risk factors, long-term complications, and treatment options was limited; at least 1 member of each group had misconceptions about HZ.
Most respondents were unfamiliar with HZ vaccines, and knowledge was limited even among HZ patients. Nevertheless, respondents expressed desire to learn more about HZ and HZ vaccination, including the risks and benefits of, suitable target population for, and ways to access HZ vaccines. Physicians and the government were perceived as reliable sources of information with significant influence on their vaccination decisions. Respondents also shared that personal stories from HZ-experienced family/friends influenced their attitudes towards HZ and HZ vaccines, which in turn affected vaccination behavior.
Across all respondent groups, avoiding pain and long-term complications of HZ were reported as key drivers to seeking HZ vaccination. Respondents were however deterred by the high cost of HZ vaccination, with adult children and HZ-vaccinated individuals reporting government subsidy as a motivation to receive vaccination.
Physicians
Physicians demonstrated ample knowledge of HZ, its symptoms and long-term complications, the at-risk population, and its risk of recurrence. They could also assess different HZ vaccines by factors including their nature, contraindications, side effects, and costs. Physicians reportedly prioritized vaccination for diseases with greater prevalence and perceived severity (e.g., pneumococcal disease, influenza), as well as on patient’s request. Concerns regarding out-of-pocket vaccine expense for patients and perceived hesitancy/unwillingness among patients to get vaccinated were additional barriers to their active recommendation of HZ vaccination. They acknowledged the need for government support, through official government information and subsidies, for clinical decision-making regarding HZ.
Phase 2 (Quantitative Validation): The Public
Demographics
After screening out respondents who were either unaware of HZ or had rejected preventive vaccines (Supplementary Figure S3), 550 older adults and 50 adult children were recruited (Table 1). Among the older adults included in the study, 13.1% had been vaccinated against HZ and 36.4% were current or former HZ patients. Majority were aged ≥60 years (56.7%) and mainly responsible for making their own decisions (69.3%). Among the 50 adult children included in the study, 92.0% had parents aged >60 years and 60.0% had family history of HZ; 32.0% had parents who were vaccinated against HZ, and 42.0% had parents with a current or former HZ diagnosis. More than half (54.0%) of adult children were mainly responsible for decision-making for their parent(s). Older adult and adult children respondents were recruited uniformly across regions in Japan.
TABLE 1
| Demographic/characteristic | Older adults | Adult children | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall (N = 550) | HZ vaccination status | HZ history | Overall (N = 50) | |||||||||
| Vaccinated (N = 72) | Non-vaccinated (N = 478) | HZ patients (N = 200) | HZ naïve (N = 350) | |||||||||
| n | % | n | % | n | % | n | % | n | % | n | % | |
| Gender | ||||||||||||
| Male | 318 | 57.8 | 38 | 52.8 | 280 | 58.6 | 125 | 62.5 | 193 | 55.1 | 27 | 54.0 |
| Female | 232 | 42.2 | 34 | 47.2 | 198 | 41.4 | 75 | 37.5 | 157 | 44.9 | 23 | 46.0 |
| Age | ||||||||||||
| 30–35 years | N/A | N/A | N/A | N/A | N/A | 10 | 20.0 | |||||
| 36–40 years | N/A | N/A | N/A | N/A | N/A | 12 | 24.0 | |||||
| 41–44 years | N/A | N/A | N/A | N/A | N/A | 13 | 26.0 | |||||
| 45–49 years | N/A | N/A | N/A | N/A | N/A | 15 | 30.0 | |||||
| 50–55 years | 126 | 22.9 | 15 | 20.8 | 111 | 23.2 | 42 | 21.0 | 84 | 24.0 | N/A | |
| 56–60 years | 112 | 20.4 | 16 | 22.2 | 96 | 20.1 | 45 | 22.5 | 67 | 19.1 | N/A | |
| 61–64 years | 94 | 17.1 | 13 | 18.1 | 81 | 16.9 | 35 | 17.5 | 59 | 16.9 | N/A | |
| ≥65 years | 218 | 39.6 | 28 | 38.9 | 190 | 39.7 | 78 | 39.0 | 140 | 40.0 | N/A | |
| Parent’s age | ||||||||||||
| 50–54 years | N/A | N/A | N/A | N/A | N/A | 0 | 0 | |||||
| 55–59 years | N/A | N/A | N/A | N/A | N/A | 4 | 8.0 | |||||
| 60–64 years | N/A | N/A | N/A | N/A | N/A | 8 | 16.0 | |||||
| ≥65 years | N/A | N/A | N/A | N/A | N/A | 38 | 76.0 | |||||
| Education level | ||||||||||||
| Elementary or high school | 115 | 20.9 | 14 | 19.4 | 101 | 21.1 | 39 | 19.5 | 76 | 21.7 | 7 | 14.0 |
| Vocational school | 84 | 15.3 | 11 | 15.3 | 73 | 15.3 | 24 | 12.0 | 60 | 17.1 | 7 | 14.0 |
| University and above | 348 | 63.3 | 47 | 65.3 | 301 | 63.0 | 136 | 68.0 | 212 | 60.6 | 36 | 72.0 |
| Prefer not to answer | 3 | 0.5 | 0 | 0 | 3 | 0.6 | 1 | 0.5 | 2 | 0.6 | 0 | 0 |
| Employment status | ||||||||||||
| Employed | N/A | N/A | N/A | N/A | N/A | 46 | 92.0 | |||||
| Not employed but financially independent | N/A | N/A | N/A | N/A | N/A | 4 | 8.0 | |||||
| Living with parent aged ≥50 years | ||||||||||||
| Yes | N/A | N/A | N/A | N/A | N/A | 28 | 56.0 | |||||
| No | N/A | N/A | N/A | N/A | N/A | 22 | 44.0 | |||||
| HZ vaccination status | Parent’s HZ vaccination status | |||||||||||
| Yes | 72 | 13.1 | 72 | 100.0 | 0 | 0 | 22 | 11.0 | 50 | 14.3 | 16 | 32.0 |
| No | 478 | 86.9 | 0 | 0 | 478 | 100.0 | 178 | 89.0 | 300 | 85.7 | 34 | 68.0 |
| HZ diagnosis status | Parent’s HZ diagnosis status | |||||||||||
| Former HZ diagnosis (recovered) | 190 | 34.5 | 20 | 27.8 | 170 | 35.6 | 190 | 95.0 | 0 | 0 | 15 | 30.0 |
| Current ongoing HZ | 10 | 1.8 | 2 | 2.8 | 8 | 1.7 | 10 | 5.0 | 0 | 0 | 6 | 12.0 |
| Does not have HZ | 350 | 63.6 | 50 | 69.4 | 300 | 62.8 | 0 | 0.0 | 350 | 100.0 | 29 | 58.0 |
| HZ disease severity | ||||||||||||
| Valid na | 200 | 22 | 178 | 200 | 0 | N/A | ||||||
| Mild | 100 | 50.0 | 4 | 18.2 | 96 | 53.9 | 100 | 50.0 | - | - | N/A | |
| Moderate | 92 | 46.0 | 16 | 72.7 | 76 | 42.7 | 92 | 46.0 | - | - | N/A | |
| Severe | 8 | 4.0 | 2 | 9.1 | 6 | 3.4 | 8 | 4.0 | - | - | N/A | |
| Family history of HZ | ||||||||||||
| Yes | 165 | 30.0 | 25 | 34.7 | 140 | 29.3 | 66 | 33.0 | 99 | 28.3 | 30 | 60.0 |
| No | 385 | 70.0 | 47 | 65.3 | 338 | 70.7 | 134 | 67.0 | 251 | 71.7 | 20 | 40.0 |
| Role in decision-making | Role in decision-making for parent | |||||||||||
| I am mainly responsible | 381 | 69.3 | 61 | 84.7 | 320 | 66.9 | 145 | 72.5 | 236 | 67.4 | 27 | 54.0 |
| We make decisions as a family unit | 168 | 30.5 | 11 | 15.3 | 157 | 32.8 | 54 | 27.0 | 114 | 32.6 | 23 | 46.0 |
| My children decide for me | 1 | 0.2 | 0 | 0 | 1 | 0.2 | 1 | 0.5 | 0 | 0 | N/A | |
Demographics and characteristics of public respondents (older adults and adult children) (Japan, 2023).
Older adult (aged ≥50 years) and adult children (aged 30–49 years, with parents aged ≥50 years) respondents included in the study were aware of HZ, and open to preventive vaccination. Data were rounded to the first decimal place and the sum of values may not total to 100%.
Disease severity was assessed among current/former older adult patients with HZ, only. HZ: herpes zoster; N/A: not applicable.
KAP Related to HZ
All public respondents were aware of HZ based on symptomatic description of the disease using local terms. Some respondents (older adults: 7.1%; adult children: 6.0%) were not aware of the medical term for HZ. Most respondents (older adults: 71.3%; adult children: 70.0%) recognized that HZ may recur, and approximately half recognized that HZ may lead to long-term complications (51.6%; 50.0%) (Figure 1A). Among older adults and adult children, 26.5% and 26.0%, respectively, perceived themselves/their parents to be at high risk of developing HZ, while 28.9% and 32.0% perceived themselves/their parents at low risk. Most respondents acknowledged the potential negative impact of HZ on QoL (older adults: 83.1%; adult children: 84.0%) and agreed that caring for HZ patients can be stressful (64.5%; 70.0%) (Figure 1B). Significantly higher proportions of HZ-vaccinated versus non-HZ-vaccinated older adults understood that the risk of long-term complications increases with age (87.5% versus 75.5%, p = 0.0299), and that HZ negatively impacts QoL (91.7% versus 81.8%, p = 0.0411) (Supplementary Table S2).
FIGURE 1
Public respondents identified low immunity (older adults: 72.4%; adult children: 68.0%) and stress (50.4%; 48.0%) as the top 2 risk factors for developing HZ; less than half of respondents (35.5%–40.0%; 38.0%–40.0%) identified older age (≥50 or 65 years) as a risk factor (Supplementary Table S3). While most respondents recognized pain (older adults: 82.7%; adult children: 74.0%) and rash (74.7%; 76.0%) as symptoms of HZ, less than half recognized itchiness and dryness (42.2%; 44.0%) and skin numbness (30.9%; 30.0%) as symptoms. Long-term nerve pain (54.9%; 50.0%) and skin infection/scarring (45.8%; 56.0%) were the most common long-term complications of HZ identified. Consistently higher proportions of HZ-vaccinated than non-HZ-vaccinated older adults were able to identify the long-term complications of HZ, with knowledge of long-term complications such as loss of vision (p = 0.0003), loss of hearing (p = 0.0127), mood disorders (p = 0.0029), and facial nerve paralysis (p = 0.0040) significantly higher among HZ-vaccinated than non-HZ-vaccinated individuals (Supplementary Table S2).
Nearly all (97.0%) current or former HZ patients sought medical treatment at a clinic or hospital. Among 81 HZ patients who sought treatment at a primary care physician, around one-third (37.0%) delayed doing so (i.e., ≥4 days after rash onset), with majority of these patients rationalizing that they did not seek timely treatment due to their perception that symptoms were not severe (73.3%).
KAP Related to Vaccination
Majority of public respondents were aware of HZ vaccine(s) (older adults: 80.4%; adult children: 76.0%). Respondents most commonly indicated that HZ vaccination is required for patients with low immunity or weakened immune system (71.1%; 62.0%), no previous HZ vaccination (54.7%; 42.0%), and those aged >65 years (46.9%; 54.0%).
Most public respondents were likely to seek HZ vaccination for themselves/their parents if recommended by a doctor (older adults: 78.7%; adult children: 84.0%), and to avoid painful symptoms (62.4%; 86.0%) and long-term complications (62.0%; 82.0%) of HZ (Figure 1C). Significantly higher proportions of HZ-vaccinated versus non-HZ-vaccinated older adults were likely to seek HZ vaccination for themselves if recommended by a doctor (90.3% versus 77.0%, p = 0.0365), and to avoid painful symptoms (97.2% versus 57.1%, p < 0.0001) and long-term complications (95.8% versus 56.9%, p < 0.0001) of HZ (Supplementary Table S2). Less than half of older adults were concerned about how HZ vaccines may interact with treatments for other conditions (44.7%) or with other vaccines (48.5%), affect current comorbidities (44.0%), and cause side effects (45.1%); proportions were higher among adult children (72.0%, 70.0%, 54.0%, and 70.0%, respectively) (Figure 1C).
Among non-HZ-vaccinated older adults and adult children with non-HZ-vaccinated elderly parents, 12.6% and 18.2% intended to get vaccinated and get their parents vaccinated, respectively, while approximately half (older adults: 49.4%; adult children: 57.6%) were undecided. The top factors driving HZ vaccine uptake were vaccine affordability (older adults: 49.8%; adult children: 34.0%), prevention of HZ (42.2%; 40.0%), and physician recommendation (35.5%; 48.0%) (Figure 1D). Notably, 12.4% of older adults and 28.0% of adult children reported having received recommendation for HZ vaccination from physicians or other HCPs. Local government subsidies were also considered a key driver of HZ vaccine uptake in ∼3 of 10 respondents (older adults: 31.8%; adult children: 30.0%).
Information Sources and Influence
Local media was the most common source of information on HZ and HZ vaccination across all respondents (older adults: 40.0%–47.6%; adult children: 36.0%), while HCPs were the most trusted (79.1%; 70.0%) and preferred (72.2%; 60.0%) information source. Out of several HZ disease and vaccination-related topics, older adults were most interested in the cost (62.9%) or effectiveness of HZ vaccine (59.8%), and the target population for HZ vaccination (53.5%) (Figure 2A). The top topics of interest for adult children were similar: cost of HZ vaccine (52.0%), target population for HZ vaccination (50.0%), and number of injections needed (50.0%) (Figure 2B).
FIGURE 2
Phase 2 (Quantitative Validation): Physicians
Demographics
A total of 60 physicians, comprising 20 GPs (33.3%), 20 pain clinicians (33.3%), and 20 dermatologists (33.3%), were recruited (Table 2). Most physicians (81.7%) had ≥16 years of clinical experience. Physicians were recruited uniformly across regions in Japan.
TABLE 2
| Demographic/characteristic | Overall (N = 60) | |
|---|---|---|
| n | % | |
| Gender | ||
| Male | 52 | 86.7 |
| Female | 8 | 13.3 |
| Age | ||
| <50 years | 29 | 48.3 |
| ≥50 years | 31 | 51.7 |
| Specialty | ||
| General practitioner | 20 | 33.3 |
| Dermatologist | 20 | 33.3 |
| Pain clinician | 20 | 33.3 |
| Years of experience | ||
| <16 years | 11 | 18.3 |
| ≥16 years | 49 | 81.7 |
| HZ patient load (per month) | ||
| 0–3 | 18 | 30.0 |
| 5–10 | 20 | 33.3 |
| 15–90 | 22 | 36.7 |
| Hospital setting | ||
| University hospital | 11 | 18.3 |
| National/public hospital | 18 | 30.0 |
| Others (e.g., clinic, private hospital, municipal hospital) | 31 | 51.7 |
| Vaccines administered or prescribed as part of routine clinical practice | ||
| Influenza vaccine | 46 | 76.7 |
| Pneumococcal vaccine | 43 | 71.7 |
| COVID-19 vaccine | 41 | 68.3 |
| HZ vaccine | 52 | 86.7 |
Demographics and characteristics of physician respondents (Japan, 2023).
Data were rounded to the first decimal place and the sum of values may not total to 100%. COVID-19: coronavirus disease; HZ: herpes zoster.
KAP Related to HZ
Majority of physicians knew the risk factors for HZ, with over three-quarters identifying these as taking immunosuppressive medications (85.0%), being ≥50 years of age (78.3%), and having chronic medical conditions (76.7%) (Supplementary Table S4). While most physicians identified PHN (96.7%) and facial nerve paralysis (63.3%) as long-term complications associated with HZ, less than half recognized other long-term complications such as loss of vision (46.7%) and skin infection/scarring (46.7%).
Awareness and knowledge of the local HZ incidence rate were low among the included physicians; overall, 13.3% were unaware and 28.3% (GPs: 30.0%; pain clinicians: 25.0%; dermatologists: 30.0%) identified the incidence rate as 10 cases per 1,000 patient years, with similar proportions believing the incidence rate was higher or lower.
Most physicians agreed that HZ negatively impacts overall QoL (93.3%), and that it is important to educate the public about both HZ disease (91.7%) and seeking treatment early on presentation of HZ symptoms (88.3%; Figure 3A).
FIGURE 3
KAP Related to Vaccination
Majority of physicians (85.0%) perceived HZ vaccination to be important to recommend to their patients aged ≥50 years, and 78.3% recommended, prescribed, and/or administered it to their patients in this age group within the 6-month period prior to the survey. Before recommending HZ vaccination to those aged ≥50 years, physicians most commonly considered the patient’s level of immunosuppression or severity of underlying diseases (70.0%), patient willingness or motivation to be vaccinated (68.3%), and age (66.7%).
The following HZ vaccine-related information topics were of greatest importance to physicians: contraindications to HZ vaccines (78.3%) and age at which HZ vaccination is indicated (78.3%) (Figure 2C). Over three-quarters of physicians (76.7%) deemed national guidelines and recommendations for HZ vaccines to be a topic of importance.
Majority agreed that it is important to educate the general population about HZ vaccination (83.3%), for people to be vaccinated to reduce risks of long-term complications from HZ (80.0%), and to prioritize patients with certain underlying conditions for HZ vaccination (73.3%) (Figure 3B). Notably, 53.3% of physicians agreed that official government information, and guidelines or campaigns would influence their recommendation of HZ vaccination.
Physician-Patient Communication
Physicians recounted having initiated conversations about HZ disease and vaccination with a mean proportion of 25.3% patients aged ≥50 years, in the 1-year period prior to the survey. They identified the cost of vaccination (51.7%) and patient willingness to be vaccinated (51.7%) as the top 2 barriers when initiating conversations about HZ vaccination with patients aged ≥50 years (Figure 4). Other factors such as limited time during appointments (41.7%) and patient’s low ability to understand the disease (40.0%) were also perceived as barriers.
FIGURE 4
Discussion
This study is among the first to evaluate KAP regarding HZ and HZ vaccination among the public and physicians in Japan. While study findings indicated high (>75%) awareness of HZ and HZ vaccines among the public, knowledge about HZ symptoms, long-term complications, risk, risk factors, and management was lacking, mirroring trends observed in other countries [35, 38, 39]. HZ-vaccinated individuals had greater awareness and knowledge of HZ risk factors and long-term complications, suggesting knowledge gaps could underlie reluctance to vaccinate against HZ. Studies have likewise shown that more non-HZ-vaccinated than HZ-vaccinated individuals perceived HZ could be “controlled” without a vaccine [39], and that greater HZ knowledge was associated with higher vaccine acceptability [40].
Despite high (>75%) awareness of the negative impact of HZ on QoL, only ∼1 in 10 older adults and 3 in 10 older adult parents of adult children were fully vaccinated against HZ. The intention to get vaccinated/get their parents vaccinated against HZ was also low among unvaccinated older adults/adult children with unvaccinated parents. This discordance between awareness of disease burden and vaccination practice could be attributed to barriers to HZ vaccine uptake such as lack of physician recommendation and vaccine affordability, both of which were identified as key drivers of HZ vaccination.
Physician recommendation was identified as a key factor influencing HZ vaccination-seeking behavior among the public; past studies have similarly shown that physician recommendation substantially increased acceptability of HZ vaccination, and even reversed patient rejection of HZ vaccination [36, 38–42]. Furthermore, the apparent congruence between rate of vaccine recommendation and vaccination status in Japan (66.7% of HZ-vaccinated older adults received HZ vaccine recommendation from family/friends/physicians/other HCPs, versus 15.5% of non-HZ-vaccinated older adults) suggests that recommendation could drive vaccine uptake. A previous study also found that HZ-vaccinated individuals were more likely than non-HZ-vaccinated individuals to have been recommended the HZ vaccine by vaccinated relatives/friends or HCPs [39].
However, physician-perceived barriers could limit conversations with patients regarding HZ and HZ vaccination. Notably, only one-quarter of physicians had initiated such conversations during their consultations in the 1-year period prior to the survey, with half potentially refraining from recommending HZ vaccines due to perceived low patient willingness/motivation to vaccinate and concerns about vaccine affordability. Correspondingly, a global systematic review and meta-analysis reported financial concerns as contributing factors to vaccination unwillingness, with only 1 in 2 individuals willing to vaccinate against HZ [42]. In the current study, the public’s low intent to vaccinate could also relate to their lack of knowledge about HZ long-term complications; only about half understood that HZ could cause long-term complications. Physician knowledge of long-term HZ complications was likewise lacking, with under half recognizing complications other than PHN and facial nerve paralysis. Given that preventing long-term complications of HZ would motivate the public’s vaccination-seeking behavior and is considered by physicians to be an important rationale for HZ vaccination, improving knowledge of the negative effects of HZ could encourage physicians to initiate HZ-related conversations with patients and increase patient willingness to seek vaccination.
Furthermore, vaccine affordability/cost was the top topic-of-interest and driving factor for vaccine uptake among the public. This is consistent with previous studies highlighting a lack of willingness to pay out-of-pocket for unsubsidized vaccines [35, 36, 38, 40, 43]. With nearly one-third of public respondents considering local government subsidy a key driver of HZ vaccine uptake, subsidies may support vaccination behavior among the community and HCPs locally. At the time of the study, HZ vaccination was not included in Japan’s NIP, and its recent integration into the NIP in April 2025 is anticipated to improve uptake by increasing access within the community. However, subsidies only partially cover vaccine cost, and are limited to adults aged ≥65 years and individuals aged 60–64 years immunocompromised due to HIV infection who are unable to perform activities of daily living, suggesting that financial barriers to HZ vaccination may remain.
Beyond the provision of subsidies, raising public awareness of their availability via government-led efforts and/or HCP sharing would be crucial in facilitating access. Official government information, guidelines, and campaigns related to HZ could inform physician recommendation of HZ vaccination and potentially address vaccine uptake. Moreover, public respondents indicated that local media was their most common source of information about HZ and HZ vaccination, while HCPs were their most trusted and preferred information source. Given that public trust in government sources, public health institutions, traditional news media outlets, and primary care physicians have been strong determinants of COVID-19 vaccine uptake in Japan [44, 45], these avenues may be effective means to reinforce best practices in HZ prevention and management.
Compared with the regional study (unpublished manuscript), KAP related to HZ and its vaccination in Japan differed to varying degrees. For example, vaccine affordability was a greater barrier to initiating HZ and HZ vaccination-related conversations for physicians in Japan (51.7%) than for those in the regional study (33.6%); in contrast, having more urgent or acute issues to address during consultations was less of a concern for physicians in Japan (36.7%; regional study: 83.6%). In both studies, physicians cited low patient willingness to vaccinate as a key barrier to recommending HZ vaccines.
Limitations
No causal associations can be made from this self-administered, self-reported survey. Recall bias may have affected findings as responses could not be cross-checked or validated. For example, reporting bias could arise from differences in determining HZ awareness during screening (based on symptomatic description of HZ using local terms) versus during the survey (based on identifying HZ from a list of diseases). Specifically, the list of medical disease terms used in the survey could have contributed to cognitive overload and hence reporting bias, where a small subset of public respondents (older adults: 7.1%; adult children: 6.0%) who were aware of HZ as a disease were not aware of its medical term. Nevertheless, the screener confirming eligibility for survey participation ensured that all public respondents were aware of HZ as a disease.
Additionally, the study excluded respondents who are unaware of HZ or rejectors of preventative vaccines, as several interview/survey questions would not be relevant to them. The online survey format further excluded respondents who lack digital literacy. This purposive/selective sampling may thus have introduced selection bias, and study findings may not be representative of the overall Japanese population.
Finally, the physicians surveyed included only GPs, dermatologists, and pain clinicians, as these specialties are the most frequently involved in managing HZ cases. As KAP towards HZ and HZ vaccination may differ across specialties, study findings may not be representative of all physicians in Japan.
Conclusion
This study reported the capability, opportunity, and motivation factors that could be addressed to overcome barriers hindering HZ vaccine uptake among patients aged ≥50 years in Japan. Overall, the public’s knowledge about HZ was low, and HZ vaccine affordability limited both vaccine recommendation by physicians and vaccine uptake among the public. Increased government-led education efforts to improve the knowledge of HZ, particularly its long-term complications, may encourage patient-physician discussions regarding HZ and support vaccine-seeking behavior given the influence of physician recommendation. Facilitating HZ vaccine access via providing and raising awareness of subsidies could further encourage joint patient-physician decision-making for HZ prevention.
Statements
Ethics statement
This study involving humans was approved by Pearl Institutional Review Board (IRB). The study was conducted in accordance with local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.
Author contributions
Substantial contributions to study conception and design: YS, SI, JC, JS, VX, VG, TI, JN, and SS; substantial contributions to analysis and interpretation of the data: YS, SI, JC, JS, VX, VG, TI, JN, and SS; drafting the article or revising it critically for important intellectual content: YS, SI, JC, JS, VX, VG, TI, JN, and SS; final approval of the version of the article to be published: YS, SI, JC, JS, VX, VG, TI, JN, and SS. All authors contributed to the article and approved the submitted version.
Funding
The author(s) declare that financial support was received for the research and/or publication of this article. This study was sponsored by GSK (study identifier eTrack 217907). Support for third-party writing assistance for this article, provided by Rachel Tan, Costello Medical, Singapore, was funded by GSK in accordance with Good Publication Practice (GPP 2022) guidelines (http://www.ismpp.org/gpp-2022).
Acknowledgments
The authors acknowledge Aylin Sever, and Audrey Colliou, GSK, for operational support. The authors also thank Costello Medical for editorial assistance and publication coordination, on behalf of GSK, and acknowledge Rachel Tan, Costello Medical, Singapore, for medical writing and editorial assistance based on authors’ input and direction.
Conflict of interest
Author YS was formerly employed by GSK. Author SI received speaker fees from GSK and Maruho, and a research grant from Maruho. Authors JC and SS are employed by and hold financial equities in GSK. Authors JS and VG were formerly employed by Oracle Life Sciences, which received fees related to the conduct of this study from GSK. Author VX is employed by Oracle Life Sciences, which received fees related to the conduct of this study from GSK. Author TI is employed by GSK. Author JN was formerly employed by and held financial equities in GSK.
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Supplementary material
The Supplementary Material for this article can be found online at: https://www.ssph-journal.org/articles/10.3389/ijph.2025.1608121/full#supplementary-material
References
1.
ImafukuSMatsukiTMizukamiAGotoYde SouzaSJegouCet alBurden of Herpes zoster in the Japanese Population with Immunocompromised/Chronic Disease Conditions: Results from a Cohort Study Claims Database from 2005-2014. Dermatol Ther (Heidelb) (2019) 9(1):117–33. 10.1007/s13555-018-0268-8
2.
van OorschotDVrolingHBungeEDiaz-DecaroJCurranDYawnB. A Systematic Literature Review of Herpes zoster Incidence Worldwide. Hum Vaccin Immunother (2021) 17(6):1714–32. 10.1080/21645515.2020.1847582
3.
DroletMBrissonMSchmaderKELevinMJJohnsonROxmanMNet alThe Impact of Herpes zoster and Postherpetic Neuralgia on Health-Related Quality of Life: A Prospective Study. CMAJ (2010) 182(16):1731–6. 10.1503/cmaj.091711
4.
JohnsonRWBouhassiraDKassianosGLeplègeASchmaderKEWeinkeT. The Impact of Herpes Zoster and Post-Herpetic Neuralgia on Quality-of-Life. BMC Med (2010) 8:37. 10.1186/1741-7015-8-37
5.
KatzJCooperEMWaltherRRSweeneyEWDworkinRH. Acute Pain in Herpes zoster and Its Impact on health-related Quality of Life. Clin Infect Dis (2004) 39(3):342–8. 10.1086/421942
6.
NojiriSItohHKasaiTFujibayashiKSaitoTHiratsukaYet alComorbidity Status in Hospitalized Elderly in Japan: Analysis from National Database of Health Insurance Claims and Specific Health Checkups. Sci Rep (2019) 9(1):20237. 10.1038/s41598-019-56534-4
7.
SaitoYIgarashiANakayamaTFukumaS. Prevalence of Multimorbidity and Its Associations With Hospitalisation or Death in Japan 2014-2019: A Retrospective Cohort Study Using Nationwide Medical Claims Data in the middle-Aged Generation. BMJ Open (2023) 13(5):e063216. 10.1136/bmjopen-2022-063216
8.
BatramMWitteJSchwarzMHainJUltschBSteinmannMet alBurden of Herpes zoster in Adult Patients with Underlying Conditions: Analysis of German Claims Data, 2007-2018. Dermatol Ther (Heidelb) (2021) 11(3):1009–26. 10.1007/s13555-021-00535-7
9.
MarraFParharKHuangBVadlamudiN. Risk Factors for Herpes Zoster Infection: A Meta-Analysis. Open Forum Infect Dis (2020) 7(1):ofaa005. 10.1093/ofid/ofaa005
10.
SteinmannMLampeDGrosserJSchmidtJHohoffMLFischerAet alRisk Factors for Herpes zoster Infections: A Systematic Review and Meta-Analysis Unveiling Common Trends and Heterogeneity Patterns. Infection (2024) 52(3):1009–26. 10.1007/s15010-023-02156-y
11.
VargheseLStandaertBOlivieriACurranD. The Temporal Impact of Aging on the Burden of Herpes zoster. BMC Geriatr (2017) 17(1):30. 10.1186/s12877-017-0420-9
12.
GrossGEEisertLDoerrHWFickenscherHKnufMMaierPet alS2k Guidelines for the Diagnosis and Treatment of Herpes zoster and Postherpetic Neuralgia. J Dtsch Dermatol Ges (2020) 18(1):55–78. 10.1111/ddg.14013
13.
OsterGHardingGDukesEEdelsbergJClearyPD. Pain, Medication Use, and health-related Quality of Life in Older Persons with Postherpetic Neuralgia: Results from a Population-based Survey. J Pain (2005) 6(6):356–63. 10.1016/j.jpain.2005.01.359
14.
ChenNLiQYangJZhouMZhouDHeL. Antiviral Treatment for Preventing Postherpetic Neuralgia. Cochrane Database Syst Rev (2014) 2014(2):CD006866. 10.1002/14651858.CD006866.pub3
15.
ChenLKAraiHChenLYChouMYDjauziSDongBet alLooking Back to Move Forward: A Twenty-Year Audit of Herpes zoster in Asia-Pacific. BMC Infect Dis (2017) 17(1):213. 10.1186/s12879-017-2198-y
16.
CurranDMatthewsSRowleySDYoungJHBastidasAAnagnostopoulosAet alRecombinant Zoster Vaccine Significantly Reduces the Impact on Quality of Life Caused by Herpes Zoster in Adult Autologous Hematopoietic Stem Cell Transplant Recipients: A Randomized Placebo-Controlled Trial (ZOE-HSCT). Biol Blood Marrow Transpl (2019) 25(12):2474–81. 10.1016/j.bbmt.2019.07.036
17.
CurranDOostvogelsLHeinemanTMatthewsSMcElhaneyJMcNeilSet alQuality of Life Impact of an Adjuvanted Recombinant Zoster Vaccine in Adults Aged 50 Years and Older. J Gerontol A Biol Sci Med Sci (2019) 74(8):1231–8. 10.1093/gerona/gly150
18.
SchmaderKEJohnsonGRSaddierPCiarleglioMWangWWZhangJHet alEffect of a Zoster Vaccine on Herpes zoster-related Interference with Functional Status and health-related quality-of-life Measures in Older Adults. J Am Geriatr Soc (2010) 58(9):1634–41. 10.1111/j.1532-5415.2010.03021.x
19.
Pharmaceuticals and Medical Devices Agency. Varicella Vaccine Live Attenuated [package insert] (2024). Available online at: https://www.pmda.go.jp/PmdaSearch/iyakuDetail/GeneralList/631340ED1 (Accessed July 26, 2024).
20.
Pharmaceuticals and Medical Devices Agency. New Drugs Approved in FY 2015 (2016). Available online at: https://www.pmda.go.jp/files/000267884.pdf (Accessed January 23, 2024).
21.
Pharmaceuticals and Medical Devices Agency. Shingrix for I.M. injection [package insert] (2023). Available online at: https://www.pmda.go.jp/PmdaSearch/iyakuDetail/GeneralList/631341B (Accessed January 23, 2024).
22.
Pharmaceuticals and Medical Devices Agency. New Drugs Approved in FY 2017 (2018). Available online at: https://www.pmda.go.jp/files/000267882.pdf (Accessed January 23, 2024).
23.
GSK. Japan’s Ministry of Health, Labour and Welfare Approves Shingrix for the Prevention of Shingles in at-risk Adults Aged 18 and over (2023). Available online at: https://www.gsk.com/en-gb/media/press-releases/japan-s-ministry-of-health-labour-and-welfare-approves-shingrix-for-the-prevention-of-shingles-in-at-risk-adults-aged-18-and-over/ (Accessed January 23, 2024).
24.
Ministry of Health, Labour and Welfare. Herpes zoster Vaccine (2025). Available online at: https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/kenkou/kekkaku-kansenshou/yobou-sesshu/vaccine/shingles/index.html (Accessed May 13, 2025).
25.
de FigueiredoASimasCKarafillakisEPatersonPLarsonHJ. Mapping Global Trends in Vaccine Confidence and Investigating Barriers to Vaccine Uptake: A large-scale Retrospective Temporal Modelling Study. Lancet (2020) 396(10255):898–908. 10.1016/S0140-6736(20)31558-0
26.
SaitohAOkabeN. Current Issues with the Immunization Program in Japan: Can We Fill the Vaccine Gap. Vaccine (2012) 30(32):4752–6. 10.1016/j.vaccine.2012.04.026
27.
DubeELabergeCGuayMBramadatPRoyRBettingerJ. Vaccine Hesitancy: An Overview. Hum Vaccin Immunother (2013) 9(8):1763–73. 10.4161/hv.24657
28.
ZhengHJiangSWuQ. Factors Influencing COVID-19 Vaccination Intention: The Roles of Vaccine Knowledge, Vaccine Risk Perception, and Doctor-Patient Communication. Patient Educ Couns (2022) 105(2):277–83. 10.1016/j.pec.2021.09.023
29.
MichieSvan StralenMMWestR. The Behaviour Change Wheel: A New Method for Characterising and Designing Behaviour Change Interventions. Implement Sci (2011) 6:42. 10.1186/1748-5908-6-42
30.
ChenJShantakumarSSiJGowindahRParikhRChanFet alKnowledge, Attitude, and Practice Toward Herpes Zoster (HZ) and HZ Vaccination: Concept Elicitation Findings From a Multi-Country Study in the Asia Pacific. Hum Vaccin Immunother (2024) 20(1):2317446. 10.1080/21645515.2024.2317446
31.
AkakuraKBoltonDGrilloVMermodN. Not all Prostate Cancer Is the Same - Patient Perceptions: An Asia-Pacific Region Study. BJU Int (2020) 126(Suppl. 1):38–45. 10.1111/bju.15129
32.
FerranteJMFyffeDCVegaMLPiaseckiAKOhman-StricklandPACrabtreeBF. Family Physicians' Barriers to Cancer Screening in Extremely Obese Patients. Obesity (Silver Spring) (2010) 18(6):1153–9. 10.1038/oby.2009.481
33.
McMullenSHessLMKimESLevyBMohamedMWaterhouseDet alTreatment Decisions for Advanced Non-Squamous Non-small Cell Lung Cancer: Patient and Physician Perspectives on Maintenance Therapy. Patient (2019) 12(2):223–33. 10.1007/s40271-018-0327-3
34.
BaalbakiNAFavaJPNgMOkoraforENawazAChiuWet alA Community-Based Survey to Assess Knowledge, Attitudes, Beliefs and Practices Regarding Herpes Zoster in an Urban Setting. Infect Dis Ther (2019) 8(4):687–94. 10.1007/s40121-019-00269-2
35.
LamACChanMYChouHYHoSYLiHLLoCYet alA Cross-Sectional Study of the Knowledge, Attitude, and Practice of Patients Aged 50 Years or Above Towards Herpes Zoster in an Out-Patient Setting. Hong Kong Med J (2017) 23(4):365–73. 10.12809/hkmj165043
36.
YangTUCheongHJSongJYNohJYKimWJ. Survey on Public Awareness, Attitudes, and Barriers for Herpes zoster Vaccination in South Korea. Hum Vaccin Immunother (2015) 11(3):719–26. 10.1080/21645515.2015.1008885
37.
BiddlecomANapapornCOfstedalMB. Intergenerational Support and Transfers. In: HermalinAI, editor. The Well-Being of the Elderly in Asia: A Four-Country Comparative Study. Ann Arbor, Michigan: University of Michigan Press (2002). p. 185.
38.
AlleftLAAlhosainiLSAlmutlaqHMAlshayeaYMAlshammariSHAldosariMAet alPublic Knowledge, Attitude, and Practice Toward Herpes zoster Vaccination in Saudi Arabia. Cureus (2023) 15(11):e49396. 10.7759/cureus.49396
39.
BricoutHTorcel-PagnonLLecomteCAlmasMFMatthewsILuXet alDeterminants of Shingles Vaccine Acceptance in the United Kingdom. PLoS One (2019) 14(8):e0220230. 10.1371/journal.pone.0220230
40.
RohNKParkYMKangHChoiGSKimBJLeeYWet alAwareness, Knowledge, and Vaccine Acceptability of Herpes Zoster in Korea: A Multicenter Survey of 607 Patients. Ann Dermatol (2015) 27(5):531–8. 10.5021/ad.2015.27.5.531
41.
TeeterBSGarzaKBStevensonTLWilliamsonMAZeekMLWestrickSC. Factors Associated with Herpes zoster Vaccination Status and Acceptance of Vaccine Recommendation in Community Pharmacies. Vaccine (2014) 32(43):5749–54. 10.1016/j.vaccine.2014.08.040
42.
WangQYangLLiLLiuCJinHLinL. Willingness to Vaccinate Against Herpes zoster and its Associated Factors Across WHO Regions: Global Systematic Review and Meta-Analysis. JMIR Public Health Surveill (2023) 9:e43893. 10.2196/43893
43.
LuXLuJZhangFWagnerALZhangLMeiKet alLow Willingness to Vaccinate Against Herpes zoster in a Chinese Metropolis. Hum Vaccin Immunother (2021) 17(11):4163–70. 10.1080/21645515.2021.1960137
44.
CaoAUetaMUchiboriMMurakamiMKunishimaHSantoshKRet alTrust in Governments, Public Health Institutions, and Other Information Sources as Determinants of COVID-19 Vaccine Uptake Behavior in Japan. Vaccine (2024) 42(17):3684–92. 10.1016/j.vaccine.2024.04.081
45.
OkadaHOkuharaTGotoEKiuchiT. Associations Between Vaccination Behavior and Trust in Information Sources Regarding COVID-19 Vaccines Under Emergency Approval in Japan: A Cross-Sectional Study. Vaccines (Basel) (2023) 11(2):233. 10.3390/vaccines11020233
Summary
Keywords
herpes zoster, herpes zoster vaccination, Japan, knowledge attitudes and practices, survey
Citation
Suzaki Y, Imafuku S, Chen J, Si J, Xiang V, Grillo V, Imai T, Naidoo J and Shantakumar S (2026) Assessing Knowledge, Attitudes, and Practices Towards Herpes Zoster and Vaccination in Japan Using the Capability-Opportunity-Motivation-Behavior Model: a Mixed-Methods Study. Int. J. Public Health 70:1608121. doi: 10.3389/ijph.2025.1608121
Received
01 November 2024
Revised
23 July 2025
Accepted
28 August 2025
Published
13 March 2026
Volume
70 - 2025
Edited by
Abanoub Riad, Masaryk University, Czechia
Reviewed by
Mohamed Lounis, Ziane Achour University of Djelfa, Algeria
Updates
Copyright
This work is authored by Suzaki, Imafuku, Chen, Si, Xiang, Grillo, Imai, Naidoo and Shantakumar. © 2026 GlaxoSmithKline Biologicals SA.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Jing Chen, jing.j.chen@gsk.com
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