https://orcid.org/0000-0003-4691-7802
ABSTRACT
Background
Herpes zoster vaccine (HZV) has been available in China’s mainland since June 2020. This study estimated willingness to receive HZV to characterize factors that may influence vaccination willingness.
Methods
We conducted a face-to-face questionnaire survey in adults aged 50–69 years in 13 communities in Shanghai in late 2020. We explored the relationship between vaccination willingness and independent factors including demographic factors, medical history, knowledge of herpes zoster and HZV, and vaccine hesitancy. Outcomes included participants’ willingness to vaccinate themselves, their partners, and their parents, under both the current payment scenario (self-payment) and a hypothetical scenario (payment by basic medical insurance).
Results
A total of 1672 respondents aged 50–69 years were included in this study. The proportion of respondents willing to get vaccinated was 16.57% for themselves, 13.88% for their partners, and 8.49% for their parents. If the vaccine was covered under insurance, these numbers increased to 72.25%, 62.50%, and 29.96%, respectively. Younger age, female gender, higher income, higher educational level, local residents, and lower vaccine hesitancy were associated with increased willingness to vaccinate. Knowledge of herpes zoster and HZV positively influenced the willingness in the hypothetical payment scenario.
Conclusion
We determined a very low willingness to vaccinate HZV in adults aged 50–69 years in a Chinese metropolis. Decreasing costs is important to increase coverage. Additionally, strengthening advocacy and health promotion for the vaccine will be particularly important, especially for groups with certain underlying diseases.
Introduction
Herpes zoster, or shingles, is an infectious disease caused by reactivation of varicella-zoster virus (VZV) that has been latent in the dorsal root ganglia or intracranial ganglia of the spinal cord for a long time, characterized by the appearance of herpes in clusters along the peripheral nerves on one side of the body.Citation1–3 Herpes zoster is more common among elderly and people with immunodeficiency, in which approximately 22% of the cases may progress to postherpetic neuralgia (PHN). The pain can last for months and even years, and seriously affects the quality of life.Citation4 Data from Canada, Israel, Japan, China and the USA estimated the age-adjusted incidence of herpes zoster to be 3.4/1000 person-years – 5.0/1000 person-years.Citation5 A study in 27 European countries showed that the incidence rate for people over 50 years old was 9.92/1000 person-years, and increased with age.Citation6 Compared to healthy people, incidence of herpes zoster may be higher in people with immunodeficiency and certain underlying diseases. Studies found that bone marrow or stem cell transplant recipients (43.03/1000 person-years) had a higher incidence than solid organ transplant recipients (17.04/1000 person-years).Citation7 In addition, people with diabetes were more susceptible to herpes zoster, as previously documented in Japan and Israel.Citation8,Citation9
Two kinds of herpes zoster vaccines (HZV) have been available globally. One is the live attenuated herpes zoster vaccine Zostavax (ZVL, Merck), which is one-dose schedule and applicable for people aged 60 and above.Citation10 Another one is the recombinant zoster vaccine Shingrix (RZV, GlaxoSmithKline), which is two-dose schedule and applicable for people aged 50 and above.Citation11 Vaccination coverage of HZV has remained low, e.g.,6.1% in Canada (2009–2013) and 25.8% in the USA (2007–2013).Citation12,Citation13 There are multiple factors that could influence vaccination uptake of HZV, including age, educational level, history of herpes zoster infection, and awareness of herpes zoster and HZV.Citation14 RZV came on to the Chinese market in June 2020. Initial investigations have shown that the Chinese population ≥50 years has relatively low willingness to receive this vaccine due to its high price (one dose is CNY 1600, or approximately USD 250). With the goal of providing scientific evidence for increasing vaccination uptake in the future, this study estimated willingness to receive HZV to characterize factors that may influence vaccination willingness.
Methods
Study design
We designed a survey in adults aged 50–69 years in Shanghai, China, in late 2020. A convenience sampling strategy was employed to recruit respondents in a total of 13 urban and rural communities.
Questionnaire design
This study investigated the answers to the questions on herpes zoster and HZV, using a questionnaire which was completed by professionally trained investigators in a face-to-face manner. The content of the questionnaire included:
Demographics such as age, gender, household registration, educational level, and monthly income;
Past medical history, including herpes zoster and varicella, systemic lupus erythematosus, cardiovascular and cerebrovascular diseases, rheumatoid arthritis, diabetes, chronic respiratory diseases, malignant tumors, and other immunodeficiency diseases;
Knowledge of herpes zoster and HZV, and willingness to vaccinate themselves, their partners and parents against herpes zoster;
Vaccine hesitancy.
Scoring of answers to the questions
In order to measure the knowledge of survey respondents, we scored their answers as follows. Generally, in the questions transformed into categorical variables, 3 points were given for correct answers, 0 point for false answers, and 1 point for those answered “not sure” (). In addition, several questions were transformed into continuous variables, including principal symptoms of herpes zoster, principal incentives to herpes zoster, and transmission routes of herpes zoster, in which 1 point was given for each correct answer and overall points were counted.
Table 1. Willingness to vaccinate herpes zoster vaccines (HZV) for themselves across the demographics and answers to questions
Vaccine hesitancy was measured with a 10-item scale, with each question using a 5-point Likert scale, as described elsewhere.Citation15 Negative attitude questions toward vaccine hesitancy were scored directly; for positive attitude questions, six points were subtracted from the questions’ scores so that all items had scores in the same direction. Then, scores of vaccine hesitancy were added together to get the total score, which could range between 10 and 50.
Statistical analysis
Descriptive statistics compared the demographic characteristics of survey respondents. The proportion of respondents being willing to be vaccinated with HZV was calculated, and then was standardized according to the population demographics (age/sex distribution) in Shanghai in the 2010 census. Moreover, multivariable logistic regression analysis was employed to separately determine the factors associated with the willingness to be vaccinated with HZV for themselves, their partners, and their parents, in the current payment scenario (self-payment) and a hypothetical scenario (payment by basic medical insurance). Demographics, medical history, knowledge of herpes zoster and HZV, and vaccine hesitancy were included as independent variables. Statistical analysis was performed using the IBM SPSS 23.0 (Armonk, NY, USA). A P value <.05 was considered statistically significant.
Ethical approval
This study was approved by the Institutional Review Board (IRB) of the Fudan University School of Public Health (IRB 00002408 and FWA 00002399) under IRB #2021-04-0895 and the IRB of Minhang District Center for Disease Control and Prevention under EC-P-2020-010.
Results
Willingness to vaccinate against herpes zoster
A total of 1672 respondents aged 50–69 years were included in this study. A majority were local residents (80.74%), had an educational level of below college and university (86.72%), and moderate monthly income (67.52%) (). In the answers to the questions, respondents were relatively likely to know about higher susceptibility to herpes zoster among the elderly (61.48%) and to believe in the vaccine’s effectiveness (72.61%); in contrast, they were less likely to know about the risk of re-contracting VZV (36.06%), or to know whether or not there was enhanced susceptibility of having VZV if in contact with those had herpes zoster (29.78%). A majority were “not sure” about the target population of HZV vaccination (82.81%) or about the HZV vaccination schedule (83.97%). In addition, their average (±standard deviation) score for vaccine hesitancy was determined to be 21.67 ± 3.63, which differed significantly by monthly income (F = 5.99, P = .003).
The unstandardized proportion of respondents willing to get vaccinated was 16.57% for themselves and the proportion standardized to Shanghai’s age/sex distribution was 17.69%. In the actual payment scenario, 318 respondents were willing to vaccinate, including for themselves (n = 277; 16.57%), their partners (n = 232; 13.88%), or their parents (n = 142; 8.49%), whereas 1354 (80.98%) were unwilling to vaccinate. If the HZV would be included in basic medical insurance, the respondents willing to receive a vaccine increased greatly: for themselves (n = 1208; 72.25%), for their partners (n = 1045; 62.50%), and for their parents (n = 501; 29.96%), while 434 (25.96%) remained unwilling to vaccinate.
Factors associated with willingness to vaccinate
We performed six logistic regression models to separately determine the factors associated with the willingness to be vaccinated with HZV for themselves, their partners, and their parents, in the actual payment scenario (self-payment) and assumed scenario (payment by basic medical insurance) ().
Table 2. Factors that influence the respondents’ willingness to vaccinate herpes zoster vaccine (HZV) under two payment scenarios
In the actual scenario of self-payment, respondents aged 50–59 years, with a higher educational level, higher monthly income, and lower vaccine hesitancy were more willing to vaccinate (). In addition, those reported being “not sure” toward the schedule of HZV doses were less willing to vaccinate. However, those had lower knowledge of herpes zoster and HZV, through questions such as susceptibility of contracting VZV in contact with those who have herpes zoster, susceptibility of contacting VZV among elderly, and targeted population of HZV vaccination in China, were more likely to have higher willingness.
Table 3. Factors that influence willingness to receive herpes zoster vaccine (HZV) for themselves or give HZV to their partners and parents under actual payment scenario (self-payment)
In the hypothetical scenario that HZV would be included in basic medical insurance, age, educational level, and vaccine hesitancy had a similar impact on the willingness as they did for self-payment (). In contrast to the actual payment scenario, respondents with higher knowledge of herpes zoster and HZV were more likely to vaccinate. In addition, those with more underlying diseases were more willing to get vaccinated for themselves.
Table 4. Factors that influence willingness to receive herpes zoster vaccine (HZV) for themselves or give HZV to their partners and parents under the hypothetical scenario (payment by basic medical insurance)
Discussion
This study found that the willingness to receive HZV for themselves was only 16.57% in adults aged 50–69 years in Shanghai. Recently, a survey reported that the willingness to receive HZV was as high as 49.64% in Shanghai. This study shared similar context and settings with our study; the difference might be attributable to the measurement by questionnaires, sample size, and date of survey.Citation16 The burden of disease of herpes zoster is relatively high. The annual economic burden caused by herpes zoster and postherpetic neuralgia in China has been estimated to be as high as CNY 9.2 billion (approximately USD 1.3 billion), and this estimate includes only in-hospital medical expenses and excludes direct non-medical expenses and indirect expenses.Citation17 Thus, increasing willingness to receive HZV may improve middle-aged and elderly adults’ health, and further provides scientific evidence for subsequent formulation of immunization strategies for other adult vaccines, like influenza, pneumococcal, or COVID-19 vaccinations. However, vaccination coverage of HZV has remained low even in high-income countries, such as 20.0% and 25.8% in Greece and the USA, respectively.Citation18,Citation19 Increasing HZV uptake among the elderly has therefore become a public health concern. Under a scenario where the costs would be covered by insurance, we saw a great increase in vaccination coverage: up to 72.2% for themselves and 74.0% for themselves, a partner, or parent, suggesting that cost of vaccination is an important barrier to vaccination.
There are multiple factors influencing the willingness and uptake of HZV vaccination. In terms of willingness to vaccinate, awareness of diseases and vaccines can have an impact. In a systematic review and meta-analysis, 67.1% of the respondents in 17 countries reported that they knew little or nothing about HZV.Citation20 In a survey in Hong Kong, China, 47.1% of the respondents who had not been vaccinated with HZV did not know about HZV, and 32.4% reported insufficient information from doctors and public education campaigns.Citation14 Similarly, in our study, the respondents also had limited knowledge of herpes zoster and HZV, which may be attributable to insufficient information from vaccination clinics or other health care providers. However, we noted that some answers on the knowledge of herpes zoster and HZV, such as susceptibility of contracting VZV in contact with those who have herpes zoster, susceptibility of contacting VZV among elderly, targeted population of HZV vaccination in China, and effect of vaccination against herpes zoster, demonstrate both positive and negative impact on the willingness to vaccinate HZV under different scenarios. Prior to this study, we hypothesized that greater knowledge and awareness in the respondents would contribute to higher willingness, but our findings did not support the hypothesis. This discrepancy be explained in that knowledge and awareness of herpes zoster and HZV may play a minor role in the decision to take the vaccination, compared to the significant role of the high price of HZV; in a hypothetical scenario where insurance covered the vaccine, vaccination willingness remarkably increased and then knowledge and awareness influenced the willingness as we had hypothesized.
In addition, we characterized how demographic factors influenced willingness to receive a vaccine. A Canadian study found that the vaccination rates of HZV for men and women were 4.8% and 7.3%, respectively; people living in urban centers (6.2%) had a higher vaccination rate than those living in rural areas (5.3%), suggesting that demographics also affected vaccination behavior.Citation13 Our study identified similar demographic factors, including younger age, female, higher income, higher educational level, and local residents, which were associated with increased willingness to vaccinate HZV. We also found that vaccine hesitancy affected the willingness to vaccinate. Interestingly, vaccine hesitancy differed significantly in the respondents with diverse income in this study, further suggesting the impact of high price of HZV.
This study has several limitations. First, this study recruited the respondents in only 13 communities, which may have limited representation. Second, this study used a face-to-face survey to fill out the questionnaire, so the respondents may tend to choose a more positive answer due to the Hawthorne effect.
In conclusion, we determined a very low willingness to vaccinate HZV in adults aged 50–69 years in a Chinese metropolitan population under the current scenario of self-payment. To increase vaccination coverage, identifying ways to decrease the price or to cover it under public funding or insurance programs will be very important. The lack of knowledge and awareness of the vaccine and the disease was also problematic. Increasing this knowledge will be particularly important among populations with certain underlying diseases.
Authors’ contribution
YL and JL conceived of this study. XL, YL, FZ and ALW drafted initial manuscript, and analyzed data. JL, XL, LZ, and KM collected the data. ALW and BG revised the manuscript and helped interpret data. All authors reviewed the final manuscript.
Disclosure of potential conflicts of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Acknowledgments
We appreciate the respondents completed the questionnaire.
Additional information
Funding
References
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