This was a multicenter study with participation by dermatology clinics from the following six university hospitals in South Korea: Konkuk University Hospital, Seoul; Seoul St. Mary's Hospital, Seoul; St. Paul's Hospital, Seoul; Inha University Hospital, Incheon; Chung-Ang University Hospital, Seoul; and Kyung Hee University Hospital at Gangdong. During the period from January to August 2014, the research team members collected data from eligible patients by using a questionnaire developed by the investigators. A total of 607 patients participated in this study. The patients were informed that the questionnaire was anonymous and confidential, and all who agreed to be involved provided verbal or written informed consent to participate. The protocol was approved by the institutional review board of each institution (IRB number of principal investigator's institution: KUH 1120045), in accordance with the principles of Good Clinical Practice and the Helsinki Guidelines.

The questionnaire (comprising 16 questions) was structured into the following four main parts: (i) sociodemographic characteristics of the participants (Q1~Q5, Q10), (ii) awareness of HZ (Q6~Q8), (iii) knowledge about HZ and its vaccination (Q9~Q12), and (iv) acceptability of HZ vaccination (Q13~Q16). The survey included questions concerning residence, age, sex, educational level, personal medical history (including cardiovascular diseases, diabetes mellitus, cancer, gastrointestinal diseases, and renal diseases), personal history of HZ, and a family history of HZ. The respondents were allowed to choose multiple answers for the question about personal medical history. The respondents scored the severity of cancer, heart disease, hypertension, diabetes mellitus, cerebral diseases, HZ, and atopic dermatitis (range, 1~5). To assess the awareness of HZ, the participants were asked whether they had ever heard of the disease. Furthermore, knowledge about HZ and its vaccination was addressed by using 14 questions with answer choices of "yes," "no," and "do not know"; the questions were on the pathophysiology and epidemiology of HZ (Q1~Q4), symptomatology and sequelae of HZ (Q5~Q8), and HZ vaccines (Q9~Q14). Respondents with a history of HZ were asked to choose which of the following symptoms they found to be the most difficult to tolerate: acute pain and itching sensation, acute vesicles and rash, sensory disturbances, PHN, postherpetic scar, and infections; the respondents were allowed to choose multiple answers. They were also asked to evaluate the degree of pain from HZ on a visual analogue scale (VAS) ranging from 0 to 10. The participants' history of HZ vaccination was queried, and if none, they were asked about their willingness to receive HZ vaccination in the future. Depending on the respondents' answers about their willingness to receive HZ vaccination, additional questions were posed concerning their reasons for and against receiving the vaccination.

The patient survey data were analyzed by using PASW Statistics ver. 17.0 (IBM Co., Armonk, NY, USA). To examine the differences in proportions and means, the two-sample t-test was used for continuous variables, and the χ² test was used for categorical variables. The relation between age and HZ knowledge was analyzed by using Spearman's rank correlation coefficient. The ANOVA trend test was used to analyze the participants' knowledge according to their educational status. Univariable logistic regression was applied to each variable to identify possible associations with HZ vaccination and willingness to receive the HZ vaccination, and then all characteristics with p-values of <0.10 were included in the multivariable logistic regression. We examined the HZ vaccination rate and willingness to receive the HZ vaccination by using multivariable logistic regression analysis while controlling for demographic characteristics (sex, age, educational status, residence area, personal history of HZ, and family history of HZ) and attitudinal characteristics (HZ knowledge and awareness, HZ vaccination history, and willingness to receive the HZ vaccination). Except where stated otherwise, the data were presented as mean±standard deviation (SD) or % values, and the cutoff for statistical significance was set at p<0.05.

A total of 607 participants (41.6% male and 58.4% female) took part in this survey; their demographic characteristics are presented in Table 1 (n varies between items because of missing data). The mean age of the participants was 47.3±15.8 years (range, 13~88 years). Most participants were older than 50 years; the age distribution was as follows: 10~19 years, n=5 (0.8%); 20~29 years, n=105 (17.5%); 30~39 years, n=91 (15.2%); 40~49 years, n=87 (14.5%); 50~59 years, n=166 (27.7%); 60~69 years, n=109 (18.2%); 70~79 years, n=24 (4.0%); and ≥80 years, n=13 (2.2%). With respect to residence, most patients (n=502, 82.8%) lived in an urban area, whereas the remaining 104 (17.2%) lived in rural areas. The educational statuses of lower than middle school, lower than high school, lower than college, and higher than graduate school were reported by 74 (12.2%), 203 (33.6%), 260 (43.0%), and 68 (11.2%) patients, respectively. We surveyed the medical history of the participants, allowing them to specify more than one condition. There were 128 participants with cardiovascular disease, 53 with diabetes, 31 with cancer, 114 with gastrointestinal disease, and 17 with renal disease (Fig. 1). A history of HZ was present in 14.7% of 606 respondents. Among responders who are 50 years of age or older, 21.2% (66 patients) responded about having a history of HZ. Of those with a medical history of more than three conditions, 12 (67.0%) had a history of HZ. One hundred sixty-nine of all 602 respondents (28.1%) had a family history of HZ.

The participants (n=607) were asked if they had ever heard of HZ; most (n=517, 85.4%) responded that they were aware of HZ (Table 2). The patients scored the severity of their diseases on a range from 1 to 5: cancer and cerebral diseases were scored highest, followed by cardiac diseases, diabetes mellitus, hypertension, HZ, and atopic dermatitis. The severity scores of HZ were distributed as follows: 1, 45 patients (7.7%); 2, 77 patients (13.2%); 3, 203 patients (34.7%); 4, 132 patients (22.6%); 5, 98 patients (16.8%); and "do not know of HZ," 30 patients (5.1%). Thus, most of the patients scored HZ with more than moderate disease severity (74.0% of patients assigned HZ with a score of ≥3).

The symptoms perceived to be the least tolerable among the patients with a history of HZ were acute pain and itching sensation (47 patients), followed by PHN (32 patients), acute vesicles and rash (19 patients), sensory disturbance (7 patients), and postherpetic scar and infections (5 patients) (Fig. 2). The VAS for the severity of pain, which was completed by 92 patients, was 7.0±2.6 (mean±SD). Most complaints were of greater than moderate pain, with 77 patients (83.7%) assigning a VAS score of >5 (Fig. 3).

The percentage of correct answers to questions about HZ and its vaccine was 42.3±25.3%. Women had more knowledge of HZ than men (45.2±24.4% vs. 38.0±25.7%, p=0.0006). The rate of correct answers did not differ significantly between those who lived in urban areas (42.6±25.6%) and those who lived in rural areas (40.3±23.8%, p=0.239). Those who had a family history of HZ appeared to know more about HZ than those without (rate of correct answers: 49.1±20.8% vs. 39.8±26.4%, p<0.0001), and those with a personal history of HZ had greater knowledge than those without (rate of correct answers: 49.4±19.2% vs. 41.0±26.0%, p=0.0005). The amount of knowledge about HZ decreased with increasing age (r=-0.18, p<0.001). The analysis of the trend of knowledge relative to educational status revealed that those with a higher educational status had greater knowledge about HZ and its vaccine (p<0.0001).

Among the responders (n=598), only 36 (6.0%) had received the HZ vaccine (Table 2); only 28 of those aged >50 years (9.0%) had received the vaccination. Univariate logistic regression analyses revealed that a personal history of HZ, a family history of HZ, awareness of HZ, increasing age, and greater knowledge about HZ and its vaccine were significantly and positively associated with vaccine acceptability (p=0.0004, 0.0622, 0.0685, 0.0011, and 0.0289, respectively; Table 3). When these significant demographic variables were entered into a multivariate model, age, history of HZ, and knowledge remained as significant predictors, such that those with a history of HZ were 2.23 times more likely to accept the vaccine than those without a history (95% confidence interval [CI], 1.03~4.83). The vaccination rate increased with increasing age (odds ratio [OR], 1.05; 95% CI, 1.02~1.07) and knowledge (OR, 1.02; 95% CI, 1.00~1.03) (Table 3).

Among those who had not been vaccinated (n=583), 58.3% (340 patients) were interested in receiving the vaccination (Table 2). Univariate logistic regression analysis showed that awareness of HZ, increasing age, living in urban areas, and greater knowledge about HZ and its vaccine were significantly and positively associated with willingness to receive the vaccination (p=0.0003, 0.0763, 0.0853, and <0.0001, respectively). When these significant demographic variables were entered into a multivariate model, age, awareness of HZ, and knowledge remained as significant predictors, such that those with awareness of HZ were 1.80 times more likely to be willing to be vaccinated for HZ than those without (95% CI, 1.09~2.97). The willingness to receive vaccination for HZ increased significantly with age (OR, 1.02; 95% CI, 1.00~1.03) and knowledge (OR, 1.01; 95% CI, 1.01~1.02) (Table 4).

The patients were asked for the reasons underlying their willingness to receive the HZ vaccination; the most frequent answer was "severe sequelae" (114 responders), followed by "knowing someone who has HZ" (81 responders), "recommendation from a doctor or other health-care professional" (80 responders), "information from the mass media" (59 responders), and "suggestion from family or someone around me" (26 responders). A small number of participants responded with "already had an HZ history," "have poor immunity," and "do not want pain." The most common reason underlying an unwillingness to receive the vaccination was "the expensive cost of the vaccine" (123 responders), followed by "did not feel the need since no one around me is vaccinated" (114 responders), "I'm healthy enough" (102 responders), "lack of knowledge on the disease" (71 responders), and "doctors did not recommend the vaccine" (30 responders). A small number responded with "did not know that the vaccine exists," "doubtful about the efficacy of the vaccine," and "concerns about postvaccine complications."