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Preferences for Sexually Transmitted Infection and Cancer Vaccines in the United States and in China

Open AccessPublished:August 30, 2022DOI:https://doi.org/10.1016/j.jval.2022.07.019

      Highlights

      • Countries have had mixed success rolling out vaccines for sexually transmitted infections (STIs). For example, human papillomavirus vaccination lags behind hepatitis B vaccination.
      • Individuals in the United States and in China had consistently strong dispreferences for STI vaccines, although the 2 countries varied in terms of what proportion and what groups would reject vaccines altogether.
      • Rollout of future STI vaccines should also consider preferences for when the vaccine be administered and what chronic diseases the vaccine prevents.

      Abstract

      Objectives

      This study assessed preferences for hypothetical vaccines for children in 2 large vaccine markets according to how the vaccine-preventable disease is transmitted via a discrete choice experiment.

      Methods

      Surveys in China (N = 1350) and the United States (N = 1413) were conducted from April to May 2021. The discrete choice experiment included attributes of cost, age at vaccination, transmission mode of the vaccine-preventable disease, and whether the vaccine prevents cancer. Preference utilities were modeled in a Bayesian, multinomial logistic regression model, and respondents were grouped by vaccine preference classification through a latent class analysis.

      Results

      Individuals favored vaccines against diseases with transmission modes other than sexual transmission (vaccine for sexually transmitted infection [STI] vs airborne disease, in the United States, odds ratio 0.71; 95% credible interval 0.64-0.78; in China, odds ratio 0.76; 95% credible interval 0.69-0.84). The latent class analysis revealed 6 classes: vaccine rejecters (19% in the United States and 8% in China), careful deciders (18% and 17%), preferring cancer vaccination (20% and 19%), preferring vaccinating children at older ages (10% and 11%), preferring vaccinating older ages, but indifferent about cancer vaccines (23% and 25%), and preferring vaccinating children at younger ages (10% and 19%). Vaccine rejection was higher with age in the United States versus more vaccine rejection among those at the age of 18 to 24 and ≥ 64 years in China.

      Conclusion

      The public had strong preferences against giving their child an STI vaccine, and the class preferring a cancer vaccine was less accepting of an STI vaccine. Overall, this study points to the need for more education about how some STI vaccines could also prevent cancers.

      Keywords

      Introduction

      In 1974, the World Health Organization recommended that countries publicly fund 4 vaccines: Bacillus Calmette-Guérin, diphtheria-tetanus-pertussis, polio, and measles vaccines. Since 2004, this recommendation has expanded to include 6 more vaccines (hepatitis B, Haemophilus influenzae type b, pneumococcal conjugate, rotavirus, rubella, and human papillomavirus [HPV] vaccines) that prevent acute and chronic diseases encompassing sexually transmitted (STI), bloodborne, and respiratory infections.
      Summary of WHO position papers - recommendations for routine immunization. World Health Organization.
      Each year, more than 2.7 million individuals die of acute diseases caused by common vaccine-preventable diseases (VPDs), and 762 000 die of cancers secondary to viral hepatitis and HPV.
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      Most of these deaths occur in low- and middle-income countries (LMICs), and the existing paradigm is that these deaths, along with the hundreds of millions of cases of VPDs, arise due to the lack of vaccine access for families in these countries.
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      Recently though, the United States has seen large outbreaks of VPDs for which vaccines have been readily available for decades such as pertussis
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      and measles.
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      The voluntary choice not to vaccinate is especially seen in the wealthier and more educated sectors of the population, whereas outbreaks of VPDs in middle-income countries such as China (such as a large mumps outbreak in 2011-2012)
      Mumps reported cases. World Health Organization.
      is due to a lack of access to vaccines. Nevertheless, middle-income countries are not immune to the consequences of vaccine hesitancy; after the dissolution of the Soviet Union, diphtheria-tetanus-pertussis uptake fell as parents became suspicious of the vaccine, and a large outbreak of more than 50 000 cases of diphtheria spread throughout eastern Europe.
      • Garrett L.
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      A study in 5 LMICs, including China, found substantial evidence of vaccine hesitancy, particularly over concerns about safety and newer vaccines.
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      • et al.
      Comparisons of vaccine hesitancy across five low- and middle-income countries.
      Currently, there are still large outbreaks of VPDs in China—for example, more than 30 000 cases of pertussis and rubella were reported in China in 2019; in the United States, there was also a high number of pertussis cases, with 15 609 reported in 2018.
      WHO vaccine-preventable diseases: monitoring system. 2020 global summary. World Health Organization.
      Since 2000, the United States has licensed 10 new vaccines,
      • Plotkin S.L.
      • Plotkin S.A.
      A short history of vaccination.
      but research on vaccine hesitancy has not kept pace with vaccine development. The faltering rollout of the HPV vaccine in the United States is a cautionary tale on how not to inform the public about a vaccine. Before vaccine introduction, awareness of HPV was low.
      • Friedman A.L.
      • Shepeard H.
      Exploring the knowledge, attitudes, beliefs, and communication preferences of the general public regarding HPV.
      The Advisory Committee on Immunization Practices published its first set of recommendations in 2006; recommendations for routine use in males did not occur until 2011.
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      • et al.
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      ,

      Markowitz LE, Dunne EF, Saraiya M, et al. Human papillomavirus vaccination: recommendations of the Advisory Committee on Immunization Practices (ACIP) [published correction appears in MMWR Recomm Rep. 2014;63(49):1182]. MMWR Recomm Rep. 2014;63(RR-05):1-30.

      Although the HPV vaccine protects against cervical, anal, oropharyngeal, and other cancers, early recommendations did not emphasize prevention of cancer as much as later recommendations.
      • Markowitz L.E.
      • Dunne E.F.
      • Saraiya M.
      • et al.
      Quadrivalent human papillomavirus vaccine: recommendations of the Advisory Committee on Immunization Practices (ACIP).
      ,
      • Clark A.
      Should HPV vaccination be mandatory? CBS News.
      Programs that have attempted to promote HPV vaccination since its introduction in the United States have met with mixed success.
      • Walling E.B.
      • Benzoni N.
      • Dornfeld J.
      • et al.
      Interventions to improve HPV vaccine uptake: a systematic review.
      In contrast, the hepatitis B vaccine—which protects against an infection spread not only through vertical transmission but also through injection drug use or sexual intercourse—has not had such a pushback from the public, likely due to being on the pediatric vaccination schedule and being marketed as a product that protects against the development of chronic infection.
      • Hardt K.
      • Bonanni P.
      • King S.
      • et al.
      Vaccine strategies: optimising outcomes.
      Nevertheless, some researchers have argued that “desexualizing” a vaccine could have inadvertent consequences in other areas of public health, such as reducing opportunities for health educators to communicate about safe sex practices.
      • Velan B.
      • Yadgar Y.
      On the implications of desexualizing vaccines against sexually transmitted diseases: health policy challenges in a multicultural society.
      A vaccine’s period of adoption into the national immunization program is a critical window for shaping public discourse about and uptake of the vaccine. As more vaccines are formulated, determination of how best to promote these vaccines to the public will become critical. Moreover, in China, the national government has set a goal of eliminating cervical cancer by 2047, and in response local governments are rapidly launching HPV vaccination programs targeting younger females.
      • Wang X.
      Plan aims to eliminate cervical cancer. CHINADAILY.
      Multiple STI vaccines are currently in the clinical trial phase of development, with the most advanced candidates (targeting herpes simplex virus 2) projected to be licensed within 10 years.
      • Marchese V.
      • Zoppo S.D.
      • Quaresima V.
      • Rossi B.
      • Matteelli A.
      Vaccines for STIs: present and future directions.
      The future introduction of STI and other vaccines for adolescents into national immunization schedules will have to deal with a population of parents who may be skeptical about newer vaccines and for STI vaccines in particular. It will be important to understand how STI vaccines could be efficiently rolled out with parental preferences taken into consideration. Nevertheless, these preferences may vary across country. With samples taken from the United States and China, the most populous high-income and middle-income countries, respectively, this study (1) used a discrete choice experiment (DCE) to assess preferences for vaccines according to how the disease, against which the vaccine protects, is transmitted, and (2) classified individuals into preference classes using an exploratory latent class analysis (LCA). We hypothesized that there would be a strong dispreference for STI vaccines.

      Methods

      Study Population

      This cross-sectional study enrolled both parent and nonparent adults at the age of ≥ 18 years in China and the United States. Data collection occurred in April and May 2021. Participants were recruited for the internet-based survey by the research firm Dynata (Shelton, CT) through social media and advertisements. Each wave used quota sampling to ensure that the numbers of participants invited were roughly proportional to the age/gender distribution of the adult population.
      We aimed to obtain a sample of 1500 adult parents and nonparents from each country. This sample size was based on considerations for the DCE and the proportion in the sample who were parents (to ensure that we had enough sample for sensitivity analyses only including parents). In other research based on national panels, it has been found that approximately 63% of panelists are parents.
      • Gidengil C.
      • Lieu T.A.
      • Payne K.
      • Rusinak D.
      • Messonnier M.
      • Prosser L.A.
      Parental and societal values for the risks and benefits of childhood combination vaccines.
      The sample size of parents within this survey (63% of 1500 is 945) was considered an adequate sample for statistical purposes. There is no standard methodology to calculate sample size for conjoint analysis studies such as DCEs,
      • Louviere J.L.
      • Henser D.A.
      • Swait J.D.
      Stated Choice Methods: Analysis and Applications.
      but one formula for sample size is the following:
      • Orme B.K.
      Sample size issues for conjoint analysis.
      N>1000×(largestnumberofattributelevels)(numberofchoicetasks)×(numberofalternatives)


      This led to a simple random sample of 500 with 4 attribute levels, 4 choice tasks, and 2 alternatives. Our sample, of approximately 1500 in each country (or approximately 945 parents in each country), was sufficient for the purposes of the DCE.

      Attributes and Study Design

      The list of attributes is found in Table 1. Based on a review of the contrasts between HPV and hepatitis B vaccines, we selected the following attributes: cost, age at vaccine administration, transmission mode for disease that vaccine protects against, and whether the vaccine prevents cancer. We also allowed for an opt-out (ie, parents deciding not to vaccinate their child). Cost distributions were based on realistic values from the vaccines for children price list and vaccine costs within China.
      • Zhuang J.-L.
      • Wagner A.L.
      • Laffoon M.
      • Lu Y.-H.
      • Jiang Q.-W.
      Procurement of Category 2 vaccines in China.
      For ease of interpretation, we converted Chinese renminbi to US dollars using a purchasing power parity currency conversion of 4.186.
      Conversion rates - purchasing power parities (PPP). OECD.
      The ages at vaccination administration were chosen based on ages at which vaccines are commonly administered in the schedule recommended by the United States
      • Robinson C.L.
      • Bernstein H.
      • Poehling K.
      • Romero J.R.
      • Szilagyi P.
      Advisory Committee on Immunization Practices Recommended Immunization Schedule for children and adolescents aged 18 years or younger-United States, 2020.
      and China Experts Advisory Committee on Immunization Practices.
      • Zheng J.
      • Zhou Y.
      • Wang H.
      • Liang X.
      The role of the China Experts Advisory Committee on immunization program.
      The transmission modes spanned those of diseases that are currently vaccine preventable (eg, pertussis and measles being airborne/respiratory, hepatitis A being foodborne, Japanese encephalitis being mosquito borne, and hepatitis B and HPV being sexually transmitted).
      Table 1List of attributes and attribute levels in a discrete choice experiment of vaccination preferences.
      AttributeAttribute levels
      Age of vaccine administration2 years

      6 years

      12 years

      15 years
      Transmission mode for vaccine-preventable diseaseAirborne

      Foodborne

      Mosquito borne

      Sexually transmitted
      Vaccine prevents cancerYes

      No
      Cost50 USD/RMB

      100 USD/RMB

      200 USD/RMB

      400 USD/RMB
      RMB indicates renminbi; USD, US dollar.
      We used a fractional factorial design and allowed respondents to opt out of the 2 choice profiles. Each respondent answered 4 different choice sets with the prompt: “in the following questions you will be presented with a table detailing 2 different vaccines for the same disease, vaccine A and vaccine B. Choose the vaccine that you would prefer be administered to your child.” Before showing participants the choice profiles, we explained each attribute separately. After answering the questions, participants were asked how confident they were in responding to the DCE questions. We also collected standard demographic information from each participant. The surveys are available at https://doi.org/10.6084/m9.figshare.16632343.v1.

      Covariates

      Our demographic variables of interest were age, gender, education, and parenthood. For parenthood, we singled out parents of daughters at the age of 5 to 17 years to better understand the potential for gendered issues of STI vaccines. Within the United States, we also collected information on race/ethnicity, religion, and political affiliation.

      Statistical Analysis

      We conducted a Bayesian analysis of the DCE, with noninformative priors.
      SAS Institute Inc. SAS/STAT® 13.1 user’s guide-the BCHOICE procedure. SAS Institute.
      We specified a multinomial logistic regression model with the data set situated as 3 observations per person (the choice of vaccine A or B or to opt out). This model yields odds ratios (ORs) and 95% credible intervals (CrIs) (see Appendix Table 1 in Supplemental Materials found at https://doi.org/10.1016/j.jval.2022.07.019). We conducted a number of sensitivity analyses, including limiting the sample to those who indicated that they were confident in their responses and to those who were parents. Our main model includes cost of vaccine as a continuous variable, but supplementary analyses include it as a categorical variable following the original design of the conjoint analysis. These sensitivity analyses did not produce substantially different results (see Appendix Tables 2 and 3 in Supplemental Materials found at https://doi.org/10.1016/j.jval.2022.07.019). Our descriptive analyses are weighted, with raked weights
      • Izrael D.
      • Hoaglin D.C.
      • Battaglia M.P.
      A SAS Macro for balancing a weighted sample. Statistics and data analysis.
      developed based on age, gender, and region of country for both countries (and additionally race/ethnicity for the United States).
      Subsequently, we conducted an LCA to classify individuals based on their preference characteristics; an individual is assigned to the class with the highest posterior probability. Our choice in the number of classes was based on model fit and interpretability of results.
      • Garrett E.S.
      • Zeger S.L.
      Latent class model diagnosis.
      We compared classes across demographic characteristics across the estimated classes using Rao-Scott chi-square tests. We named the preference classes based on the most preferred attribute levels in each class.

      Ethical Approval

      The study protocol was reviewed by the University of Michigan Health Sciences and Behavioral Sciences Review Board (#HUM00193501) and the Fudan University School of Public Health Ethical Review Committee (institutional review board #2021-03-0887). Participants read an electronic informed consent form earlier and had to click “I agree” before answering any questions.

      Results

      In total, the online questionnaire database captured responses from 2371 individuals in the United States and 1830 individuals in China. After excluding those who did not agree to the informed consent, we had a final sample of 1413 from the United States and 1350 from China. The distribution of demographic variables is presented in Table 2. The US and Chinese samples were relatively comparable in the proportion of individuals with a high school education or less (19% in United States and 20% in China) and the proportion with a bachelor’s degree (52% in the United States and 53% in China). In both countries, a small proportion were parents of a daughter at the age of 5 to 17 years: 14% in the United States and 11% in China.
      Table 2Distribution of sociodemographic variables across US and China samples, April to May 2021.
      Demographic characteristicUS sample (N = 1413)Chinese sample (N = 1350)
      Age
       18-24273 (12)239 (11)
       25-34317 (17)367 (21)
       35-44320 (16)334 (18)
       45-54130 (16)207 (22)
       55-65147 (17)116 (15)
       ≥ 64226 (22)87 (14)
      Gender
       Female763 (51)681 (49)
       Male650 (49)669 (51)
      Educational attainment
       ≤ High school313 (19)184 (20)
       Vocational school or associate’s degree417 (29)360 (27)
       Bachelor's degree683 (52)806 (53)
      Parent of daughter 5-17 years old
       No1190 (86)1164 (89)
       Yes223 (14)186 (11)
      Race/ethnicity
       Non-Hispanic black195 (12)--
       Non-Hispanic white944 (71)--
       Hispanic128 (7)--
       Other146 (11)--
      Religion
       None398 (27)--
       Catholic232 (17)--
       Evangelical Protestant337 (23)--
       Mainline Protestant128 (11)--
       Jewish54 (4)--
       Other264 (17)--
      Political affiliation
       Democrat597 (40)--
       Independent415 (30)--
       Republican401 (30)--
      Note. Values are presented in the form of frequency (%).
      Figure 1 graphically displays results from the DCE (which is also presented, along with willingness to pay estimates, within Appendix Table 1 in Supplemental Materials found at https://doi.org/10.1016/j.jval.2022.07.019). Overall, individuals in the United States and in China preferred other vaccines over STI vaccines (reference level: vaccine for airborne disease, in the United States, OR 0.71; 95% CrI 0.64-0.78; in China, OR 0.76; 95% CrI 0.69-0.84). In the United States, individuals expressed stronger preference for a vaccine protecting against cancer (OR 1.10; 95% CrI 1.04-1.17), whereas in China the opposite association was observed (OR 0.87; 95% CrI 0.83-0.92). There were no major differences in preferences for the age at vaccination administration in China or the United States.
      Figure thumbnail gr1
      Figure 1Preferences for pediatric vaccines of various characteristics in China (n = 1350) and the United States (n = 1413); results are obtained from a Bayesian multinomial logistic regression model.
      USD indicates US dollar.
      Models fit for different numbers of classes are presented in Appendix Table 4 in Supplemental Materials found at https://doi.org/10.1016/j.jval.2022.07.019 for the United States and Appendix Table 5 in Supplemental Materials found at https://doi.org/10.1016/j.jval.2022.07.019 for China. We chose 6 classes for each country as a balance between increased fit as the number of classes increased with interpretability of the results (Appendix Table 6 in Supplemental Materials found at https://doi.org/10.1016/j.jval.2022.07.019 shows alternative results from a 5-class LCA). The composition of each class varies slightly between countries, but we were able to describe classes within each country in a similar fashion (see Appendix Tables 7 and 8 in Supplemental Materials found at https://doi.org/10.1016/j.jval.2022.07.019). Vaccine rejecters (19% in the United States and 8% in China) were those who tended to opt out of the DCE. Another class included those we describe as careful deciders (18% in the United States and 17% in China), meaning that one attribute in particular did not drive their decision making. Those with strong preferences for a cancer vaccine made up 20% of the US sample and 19% of the China sample. There were individuals grouped into classes based on whether they preferred vaccinating their child at younger ages (10% in the United States and 19% in China), at older ages (10% in the United States and 11% in China), or at older ages, but being indifferent about cancer vaccines (23% in the United States and 25% in China). Notably, the class with preferences for vaccinating at younger ages also preferred not receiving a cancer vaccine. Overall, vaccines for an STI were strongly not preferred except in the careful decider class and the class preferring cancer vaccines.
      We describe how the different classes vary by demographic composition in Table 3 (for the United States) and Table 4 (for China). The largest trends were observed in differences between being classified as a vaccine rejector or not. For the United States, there was a strong monotonic relationship between being a vaccine rejector and age, with 13% of those at the age of 18 to 24 years rejecting vaccines versus 30% in those at the age of ≥ 64 years (P < .001). In China, this was a U-shaped relationship, with the lowest levels of classification as a vaccine rejector in those at the age of 35 to 44 years (4%), but classification as a vaccine rejector relatively high for those at the age of 18 to 24 and ≥ 64 years (P < .001). In the United States, there were not significant differences in class assignment by gender, education, and whether the participant was a parent of a daughter at the age of 5 to 17 years. In China, there was a significant difference (P = .006), with lower numbers in the vaccine rejection class who were parents of daughters (4%) than those who were not (9%). In the United States, we also examined differences across race/ethnicity, religion, and political affiliation. Across race/ethnicity, the highest proportion in the vaccine rejection group was found among non-Hispanic white Americans (23%) and was relatively low among Hispanic Americans (12%). By political affiliation, vaccine rejection was highest among independents (28%) and lowest among Democrats (15%). There were no significant differences by religion.
      Table 3Demographic characteristics based on pediatric vaccine preference from a latent class analysis, United States, April to May 2021.
      Demographic characteristicVaccine rejecters, %Prefer cancer vaccines, %Prefer vaccinating older ages, %Careful deciders, %Prefer vaccinating younger ages, %Prefer vaccinating older ages, indifferent about cancer vaccines, %
      Age

      P < .001
       18-24132012211023
       25-34142311191123
       35-44142111191124
       45-542618916921
       55-6528181016820
       ≥ 643016915920
      Gender

      P = .247
       Female23201017921
       Male201910181023
      Educational attainment

      P = .121
       ≤ High school24189181022
       Vocational school or associate’s degree23181019921
       Bachelor's degree202111171022
      Parent of daughter 5-17 years old

      P = .309
       No221910171022
       Yes182010191123
      Race/ethnicity

      P = .031
       Non-Hispanic black182011191022
       Non-Hispanic white231910171021
       Hispanic122111201126
       Other201910171024
      Religion

      P = .846
       None22211016921
       Catholic211910171023
       Evangelical Protestant201811191022
       Mainline Protestant2620917919
       Jewish19191419821
       Other22199181023
      Political affiliation

      P < .001
       Democrat152211181024
       Independent28171016920
       Republican24189191021
      Note. P values from Rao-Scott chi-square tests.
      Table 4Demographic characteristics by pediatric vaccine preference from a latent class analysis, China, April to May 2021.
      Demographic characteristicVaccine rejecters, %Prefer cancer vaccines, %Prefer vaccinating older ages, %Careful decidersPrefer vaccinating younger ages, %Prefer vaccinating older ages, indifferent about cancer vaccines, %
      Age

      P < .001
       18-24132011171623
       25-3482011161827
       35-4441911202126
       45-5452112182025
       55-65101912162022
       ≥ 64141811151725
      Gender

      P = .165
       Female72012171925
       Male101911171925
      Educational attainment

      P = .095
       ≤ High school11209171925
       Vocational school or associate’s degree92013161824
       Bachelor’s degree71911181926
      Parent of daughter 5-17 years old

      P = .012
       No92011171925
       Yes42012181927
      Note. P values from Rao-Scott chi-square tests.

      Discussion

      The introduction of the HPV vaccine in the United States and in China has led to a need for new communication techniques and framing for parents compared with other childhood vaccines. After the HPV vaccine, numerous STI vaccine candidates will likely achieve licensing in the foreseeable future,
      • Gottlieb S.L.
      • Johnston C.
      Future prospects for new vaccines against sexually transmitted infections.
      and this study highlights potential pitfalls to STI vaccine promotion. Using internet-based samples in China and the United States, we sought to understand preferences in the general population for STI versus non-STI vaccines using a DCE. We found that individuals had a weaker preference for a vaccine against STI. Overall, our study highlights some challenges in introducing an STI vaccine into a population in the presence of strong preferences against STI vaccines.
      We found somewhat similar results for China and the United States in terms of opt-out, age, and transmission mode preferences. Nevertheless, there were opposite trends for preferences for a cancer vaccine and cost of the vaccine. In the United States, there was a preference for a cancer vaccine, whereas in China there was a preference for a noncancer vaccine. We will note that this could be due to low knowledge of specific cancer vaccines, such as the HPV vaccine in China. Knowledge about the vaccine and its related infection was greatly related to vaccination choices in a previous DCE of HPV vaccination preferences in Zhejiang province, China.
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      Preference and willingness to pay of female college students for human papillomavirus vaccination in Zhejiang Province, China: a discrete choice experiment.
      Hepatitis B vaccines have been publicly funded in China since 2002,
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      but the HPV vaccine has only recently been introduced into the private market in China; this lack of long-term use of multiple anticancer vaccines may indicate a lack of familiarity with these vaccines in China and accordingly less strong preferences for them. We also found that in the United States, as expected, there was a dispreference for a more costly vaccine, whereas in China the opposite association was found. Similar trends were found in previous studies.
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      Sensitivity analyses within a previous article suggested that trends in the overall population were being driven by higher income individuals valuing higher cost vaccines (perhaps out of a conflation between cost and quality), whereas individuals of lower socioeconomic status had dispreferences for higher cost vaccines, as expected.
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      We found a substantial dispreference for STI vaccines, with little difference across comparisons with other vaccines (for airborne, mosquito-borne, or foodborne illnesses). Within the United States, there has been stated concern that vaccinating adolescents against an STI could negatively influence sexual behaviors,
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      although empirical evidence has shown this to be an unfounded concern.
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      • et al.
      HPV vaccination has not increased sexual activity or accelerated sexual debut in a college-aged cohort of men and women.
      A previous qualitative study also noted that for some parents, knowing that the HPV vaccine protected against an STI was important for their decision making, but for other parents it was not as important.
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      “I think they’re all basically the same”: parents’ perceptions of HPV vaccine compared to other adolescent vaccines.
      It is also possible that preferences differ by gender of the child, and we note that only approximately 1 in 3 HPV vaccination programs worldwide vaccinates both girls and boys.

      Bruni L, Saura-Lázaro A, Montoliu A, et al. HPV vaccination introduction worldwide and WHO and UNICEF estimates of national HPV immunization coverage 2010-2019 [published correction appears in Prev Med. 2022;155:106925]. Prev Med. 2021;144:106399.

      As vaccine candidates for herpes simplex virus 2, chlamydia, and other STIs progress through clinical trial development, it will be important for industry and public health stakeholders to strategize about how to effectively increase vaccine uptake. There are other possible reasons for differences in preferences across transmission modality; it is possible that the COVID-19 pandemic has increased the relative salience of vaccines for airborne transmitted infections. It is also possible that the lower preference for STI vaccines could be due to beliefs that the infection could be prevented through other means, such as safer sex practices. Nevertheless, it is also likely that many vaccine-preventable illnesses could also be prevented through nonpharmaceutical interventions, including safer food preparation and mask wearing.
      In our LCAs, we found similar classifications for China and the United States, although the proportions varied slightly. For instance, there were more vaccine rejecters in the United States (19%) than in China (8%). Direct comparisons of vaccine attitudes across different countries are limited in the scientific literature. Nevertheless, a recent global study actually found higher proportions of individuals in the United States believing that vaccines are effective, important, and safe than in China.
      • de Figueiredo A.
      • Simas C.
      • Karafillakis E.
      • Paterson P.
      • Larson H.J.
      Mapping global trends in vaccine confidence and investigating barriers to vaccine uptake: a large-scale retrospective temporal modelling study.
      Attitudes toward vaccines in China may be shaped by some recent safety and quality scandals.
      • Zhuang J.
      • Lu Y.
      • Wagner A.L.
      • Jiang Q.
      Profit considerations in vaccine safety-related events in China.
      In contrast, coverage of mandatory pediatric vaccines in China is relatively high.
      • Wagner A.L.
      • Sun X.
      • Montgomery J.P.
      • Huang Z.
      • Boulton M.L.
      The impact of residency and urbanicity on Haemophilus influenzae type b and pneumococcal immunization in Shanghai children: a retrospective cohort study.
      In line with the results of our study, this may suggest individuals in China may have concerns about vaccines but still are willing to obtain vaccines for their children or may be strongly influenced by the presence of vaccine mandates.
      There were similar proportions of individuals in the class preferring cancer vaccines in China (19%) and in the United States (20%). Interestingly for both China and the United States, individuals in this class were more willing to consider STI vaccines than other classes. Accordingly, pushing forward a message that STI vaccines, such as HPV and hepatitis B, also protect against cancer could be motivating for vaccine acceptance, but might be less impactful among individuals of other vaccine preference classes. In the initial rollout of the vaccine, there was a large backlash over sex-related concerns. Succinct messages that frame HPV vaccine as both an STI and a cancer vaccine could be useful and be in line with public health goals to promote healthy sexual activity and to reduce rates of HPV related cancer.
      • Velan B.
      • Yadgar Y.
      On the implications of desexualizing vaccines against sexually transmitted diseases: health policy challenges in a multicultural society.
      ,
      • Huang Z.
      • Ji M.
      • Ren J.
      • et al.
      Effect of the framing of HPV vaccination on parents’ willingness to accept an HPV vaccine.
      In fact, it is important to highlight that clear communication between parents and vaccination providers is essential to increase uptake of the vaccine.
      • Rickert V.I.
      • Rehm S.J.
      • Aalsma M.C.
      • Zimet G.D.
      The role of parental attitudes and provider discussions in uptake of adolescent vaccines.
      Within the United States, age, race/ethnicity, and political affiliation were all associated with LCA classification. For all these, the most substantial differentiation was between vaccine rejecters and other categories, with little difference across the other 4 categories. This could indicate that the relationship between demographic status and vaccine attitudes is more tied to whether an individual accepts or rejects a vaccine, but not on shades of how they accept vaccines or what specific vaccines they prefer. Previous studies have also shown vaccine hesitancy to be relatively high in white Americans, with low levels of vaccination in black Americans more tied to access and affordability issues than hesitancy.
      • Williams J.T.B.
      • Rice J.D.
      • Lou Y.
      • et al.
      Parental vaccine hesitancy and vaccination disparities in a safety-net system.
      Similarly, a study in Australia found lowest vaccination coverage in the most affluent areas.
      • Bryden G.M.
      • Browne M.
      • Rockloff M.
      • Unsworth C.
      The privilege paradox: geographic areas with highest socio-economic advantage have the lowest rates of vaccination.
      Although some studies have identified some more concerns among black Americans about side effects,
      • Santibanez T.A.
      • Nguyen K.H.
      • Greby S.M.
      • et al.
      Parental vaccine hesitancy and childhood influenza vaccination.
      much of this can be tied to racial discrimination.
      • Savoia E.
      • Piltch-Loeb R.
      • Goldberg B.
      • et al.
      Predictors of COVID-19 vaccine hesitancy: socio-demographics, co-morbidity, and past experience of racial discrimination.
      We also note that we did not find a difference in class assignment across religion within the United States. Previous studies have found this relationship
      • Shelton R.C.
      • Snavely A.C.
      • De Jesus M.
      • Othus M.D.
      • Allen J.D.
      HPV vaccine decision-making and acceptance: does religion play a role?.
      (although another study actually found the reverse association).
      • Grandahl M.
      • Paek S.C.
      • Grisurapong S.
      • Sherer P.
      • Tydén T.
      • Lundberg P.
      Parents’ knowledge, beliefs, and acceptance of the HPV vaccination in relation to their socio-demographics and religious beliefs: a cross-sectional study in Thailand.
      Discrepancies across previous studies and our studies in the relationship between religion and vaccination could be due to differences in location, time, or how variables were assessed.
      Fewer studies in China have studied vaccine hesitancy patterns. A recent scoping review of this literature found that most studies position vaccine hesitancy as a result of medical misconduct or vaccine safety concerns
      • Yang R.
      • Penders B.
      • Horstman K.
      Addressing vaccine hesitancy in China: a scoping review of Chinese scholarship.
      China does have high vaccination rates, although coverage for mandatory vaccines is higher than for voluntary vaccines,
      • Wagner A.L.
      • Sun X.
      • Montgomery J.P.
      • Huang Z.
      • Boulton M.L.
      The impact of residency and urbanicity on Haemophilus influenzae type b and pneumococcal immunization in Shanghai children: a retrospective cohort study.
      and some vaccines, such as rotavirus, Haemophilus influenzae type b, pneumococcal, and HPV vaccines, are voluntary in China and thus have low coverage.
      Among LMICs, several populous countries, including Turkmenistan, Zambia, Uzbekistan, Mexico, and Rwanda, are reported to have more than 90% first dose coverage of the HPV vaccine.

      Bruni L, Saura-Lázaro A, Montoliu A, et al. HPV vaccination introduction worldwide and WHO and UNICEF estimates of national HPV immunization coverage 2010-2019 [published correction appears in Prev Med. 2022;155:106925]. Prev Med. 2021;144:106399.

      Evaluation of projects in LMICs has highlighted the needs to integrate HPV vaccination with other community health programs, including vaccination, to distribute the vaccine at schools and other locations, and to involve multiple stakeholders.
      • Wigle J.
      • Coast E.
      • Watson-Jones D.
      Human papillomavirus (HPV) vaccine implementation in low and middle-income countries (LMICs): health system experiences and prospects.
      ,
      • Markowitz L.E.
      • Tsu V.
      • Deeks S.L.
      • et al.
      Human papillomavirus vaccine introduction-the first five years.
      The examples speak to the ability to successfully promote STI vaccines in diverse settings. Vaccination coverage could also be increased through vaccine mandates.
      • Constable C.
      • Caplan A.
      Comparison of the implementation of human papillomavirus and hepatitis B vaccination programs in the United States: implications for future vaccines.

      Strengths and Limitations

      There are several limitations to this study. It is an opt-in study, such that our sample is not probability based and is biased toward those with internet access. The probability of internet access also varies between the countries. Therefore, our results need to be explored in more robust samples. We note that our sample is more educated in the general population—for example, in our study in China, 27% had a 2-year postsecondary degree, and 53% had a bachelor’s degree. The National Bureau of Statistics of China estimates these numbers to be 36% and 18%, respectively, for adults at the age of 25 to 34 years in 2020.
      National Bureau of Statistics of China
      Tables 2-25 population aged 6 and over by age, gender and education attainment.
      The US Census estimates that 35% of adults in 2020 had a bachelor’s degree and 10% had an associate’s degree
      Educational attainment in the United States: 2020. US census.
      compared with 52% and 29%, respectively, in our sample. We purposefully asked about preferences for broad groupings of VPD by transmission modality, but we acknowledge that individuals could have varied preferences for vaccines within group (eg, for an influenza vs COVID-19 vaccine or for an HIV vs gonorrhea vaccine). A strength is the similar study design in the United States and in China, which results in us being able to make direct comparisons across countries.

      Conclusions

      In this DCE, jointly conducted in the United States and in China, we found that the public, when asked about childhood vaccines, had relatively low preferences for STI vaccines versus vaccines for airborne, foodborne, or mosquito-borne infections. With an LCA, the class preferring a cancer vaccine did not accept an STI vaccine. Overall, this study points to the need for more education about how some STI vaccines can also prevent cancers and that doctors should be open in their communication with parents.

      Article and Author Information

      Author Contributions: Concept and design: Wagner, Janusz, Prosser
      Acquisition of data: Wagner, Lu
      Analysis and interpretation of data: Wagner, Janusz, Pan, Glover, Wu
      Drafting of the manuscript: Wagner, Janusz, Glover
      Critical revision of the paper for important intellectual content: Lu, Pan, Wu, Prosser
      Statistical analysis: Wagner, Glover, Wu
      Obtaining funding: Wagner, Prosser
      Administrative, technical, or logistic support: Lu, Pan
      Conflict of Interest Disclosures: The authors reported no conflicts of interest.
      Funding/Support: This article was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under award number K01AI137123. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
      Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

      Supplemental Material

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