https://orcid.org/0000-0002-9508-1098
ABSTRACT
Objective: This study aimed to assess the knowledge of Chinese dentists on human papilloma virus (HPV), their willingness and factors prevention them from recommending patients for HPV vaccination, and to identify ways through which dentists can acquire HPV-related knowledge.
Methods: This was a cross-sectional study based on Chinese dentists. The anonymous self-filled questionnaire method was used to collect demographic information of participants, their knowledge of HPV, willingness and barriers to recommending HPV vaccines to patients, and the strategies they can adopt to obtain HPV-related knowledge.
Results: A total of 517 dentists completed the questionnaire, and 89.94% of dentists were willing to recommend HPV vaccination to patients. Participants aged 30–39 years, male dentists and dentist-in-charge had relatively lower knowledge scores than other groups. Besides, participants aged 30–39 years, working in private hospitals, and practicing in Southern China had a lower willingness to recommend HPV vaccination to patients. Recommending HPV vaccination to patients is not within the scope of practicing dentists, and concerns about the safety of the HPV vaccine were found to be the main barriers preventing its recommendation. Notably, 97.87% of dentists were eager to acquire HPV-related knowledge, and agreed for the first time to enroll in relevant educational courses.
Conclusion: Chinese dentists had expressed a strong desire to recommend HPV vaccines to patients, even though their knowledge of HPV was scanty. Therefore, measures to improve their understanding of HPV vaccines and eliminate barriers suppressing their willingness to recommend HPV vaccines are urgently needed.
1. Introduction
Tobacco and alcohol exposure has long been considered the main risk factors for oropharyngeal cancer (OPC). However, in recent decades, studies have shown that the incidence of Human Papillomavirus (HPV)-related OPC is on the rise.Citation1,Citation2 In the United States and Northern Europe, about 70% of new cases of OPC are caused by HPV.Citation3,Citation4 Moreover, the number of HPV-related OPC cases in the United States has surpassed cervical cancer cases to be the most common HPV-associated cancer, with more than 13,000 new cases diagnosed each year.Citation5-7 There have been tremendous efforts to prevent and control the development of HPV and HPV-related OPC.
Since there is a causal connection between HPV and OPC, prevention of HPV infection may lower the incidence of OPC. Although many subtypes of HPV have been described, 90–95% of OPCs are caused by HPV 16 and HPV 18.Citation8 The US Food and Drug Administration (FDA) approved 3 HPV vaccines, all of which provided good protection against HPV 16 and HPV 18. Although HPV vaccine has not been approved for the prevention of OPC, some studies have shown that the vaccine has decreased the prevalence of oropharyngeal HPV infection among the vaccinated populations.Citation9-12 Recently, the American Dental Association (ADA) and American Academy of Pediatric Dentistry (AAPD) issued a statement recommending that dental professionals should play a greater role in the prevention of HPV-related OPC and promotion of HPV vaccines.Citation13,Citation14 Dental professionals contribute to the prevention of HPV- related OPC and recommends HPV vaccination to patients, this strongly promotes the pace of controlling the incidence of OPC.Citation15–17 In recent years, Chinese medical providers have paid more and more attention to the prevention and treatment of HPV-associated cancers.Citation18 We envision that Chinese dentists will play a major role in preventing HPV- related OPC and promoting the adoption of HPV vaccines.
China is the largest developing country in the world with a population of approximately 1.4 billion. During 2008–2012, the crude incidence rate of OPC in China was 3.28/100,000, and the age-standardized rates of incidence and mortality reported by Chinese standard population were 2.27/100,000 and 2.22/100,000, respectively.Citation19 Moreover, the incidence and mortality of OPC in China have been gradually increasing in recent years,Citation20 which may be ascribed to HPV infections. Regrettably, because HPV testing on OPC patients’ specimens has not been fully implemented nationwide, all epidemiological data on the prevalence of HPV-OPC in China are derived from regional studies often with small sample sizes. A study investigated HPV-related OPC in patients in southern China (Hong Kong) and found that 20.8% (43/207) of OPC was HPV-related.Citation21 In a study conducted in eastern China, Wang et al.Citation22 investigated 188 patients who were diagnosed with OPC between 2008 and 2014, and found that 21.28% (40/188) of the patients were HPV-16 positive. A recent meta-analysis covering 28 studies and 514 OPC patients showed that about 31.6% (21.7–41.5%) of OPCs in China were due to HPV16.Citation23 Although HPV-related OPC infection rate in China is lower than that of some developed countries such as the United States and Northern Europe, considering China’s huge population, sufficient attention should be paid to HPV-related OPC prevention.
After a ten-year delay since FDA licensure in 2006, the first HPV vaccine was approved for use in China in 2016. Imported vaccines such as the bivalent HPV or 2vHPV (Cervarix), quadrivalent HPV or 4vHPV (Gardasil), and nonavalent HPV or 9vHPV (Gardasil 9) were licensed by the Chinese Food and Drug Administration in July 2016, April 2017 and May 2018, respectively. In addition, the first Chinese domestic bivalent HPV vaccine (Cecolin, Innovax, China) was approved for use on December 31, 2019. These vaccines were all registered for female use. However, there is no national free or discounted vaccination plan had been established in China so far. The vaccination rate for female in China is 3%,Citation24 which is much lower than 33–80% in developed countries such as the United States, Britain and Australia.Citation25 Therefore, the priority to increase vaccination uptake and protect more people from HPV.
The clinical symptoms and treatment principles of OPC are compulsory content of dentist undergraduate education, so Chinese dentists are the highly knowledgeable population regarding OPC in China. Thus, they are expected to encounter more than 100 million patients every year.Citation26 A previous survey reported that doctors are considered to strongly convince the Chinese populations to receive the vaccination.Citation27 Besides, Chinese dentists play a significant role in educating people on the need to control tobacco and alcohol consumption and eating betel nut.Citation28 Therefore, given the role played by Chinese dentists in recommending HPV vaccination and educating people on HPV-related OPC, it is important to assess their current knowledge on HPV, HPV-related OPC and HPV vaccination. Besides, it is also important to assess their willingness and the barriers faced when communicating with patients about HPV-related OPC and HPV vaccination. To the best our knowledge, this survey provides the first assessment of the understanding of HPV-related OPC and HPV vaccine among Chinese dentists to date. This study provides useful information support subsequent HPV-related OPC prevention and vaccine popularization in China.
2. Materials and methods
2.1. Participants and study design
This cross-sectional study was conducted in mainland China in July 2020. The study subjects were dentists holding a certificate in dental practitioner qualification and engaged in the practice of dentistry in clinical diagnosis and treatment. A convenience sampling approach was used to recruit participants from 26 regions in mainland China through a social platform (WeChat). This group represented people with a vast knowledge of OPC in mainland China.
The study was conducted through the Wenjuanxing online survey system. All participants obtained the survey link by scanning the WeChat QR code to complete the survey. Each mobile terminal could only submit the questionnaire once to avoid errors caused by repeated answers.
2.2. Instruments
The questionnaire was self-filled, anonymous, and developed based on previously published and related research.Citation29-31 The questionnaire was pre-tested by 50 dentists and enhanced through modification by several experts. The 34 items questionnaire consisted of 4 parts: demographics information of the study participants, HPV-related knowledge, the intention of and barriers to recommending HPV vaccination, the intention of acquiring HPV-related knowledge and ways to acquire knowledge.
2.2.1. Demographics of study participants
The information included: gender, age, title grade, education, practice setting, marital status and practice location.
2.2.2. HPV-related knowledge
In this section, there were 23 questions, which included basic knowledge of HPV, HPV-related OPC and HPV vaccine knowledge. There were three options for each question: ‘true’, ‘false’ and ‘don’t know’. A correct answer was scored as 1, and an incorrect or “don’t know” answer was scored as 0. The number of correct answers to the knowledge scale was summed, and the score ranges for each participant was between 0 and 23. The higher score implied that participants had a high-level the knowledge level of the HPV, HPV-related OPC, and HPV vaccine knowledge.
2.2.3. Intention of and barriers to recommend HPV vaccination
After answering HPV-related knowledge, the participants were asked: “If the HPV vaccine can prevent HPV-associated cancers and you have enough knowledge about HPV, would you be willing to educate patients about HPV-related oropharyngeal cancer and recommend HPV vaccination as part of your daily work?” Participants who answered “unwilling” were asked to provide reasons for such a decision. This was a closed-end multiple choice question with 6 options. Participants were required to choose at least one option.
2.2.4. Intention of acquiring HPV-related knowledge and ways of obtaining the knowledge
After answering the previous questions, the participants were asked: “Are you willing to acquire knowledge about HPV, HPV-related OPC, and HPV vaccines?” Participants who answered “willing” were asked to give details on how they would like to obtain the relevant knowledge. This was a closed-end multiple choice question with 5 options. Participants were required to choose at least one option.
2.3. Ethical considerations
This study was approved by the Medical Ethics Committee of the Affiliated Beijing Stomatological Hospital of Capital Medical University. Participants were informed that participation was voluntarily and that they must give informed consent to participate in the survey. They were informed that the information collected would have no identifiers and that their anonymity and confidentiality would be highly protected.
2.4. Statistical analysis
SPSS 21.0 statistical software was used for data analysis and Cronbach’s Alpha coefficient was used to verify the reliability of the questionnaire. Count data were described in terms of the number of cases and percentages (%). The Chi-square test or Fisher’s exact test was used for statistical inferences between groups. Measurement data were described as mean ± standard deviation (X ± SD). An independent sample t-test was used for comparison between groups. The non-parametric rank-sum test was used for non-conformity analysis. Univariate and multivariate Logistic regression analyses were used to calculate the adjusted odds ratio (OR) and 95% confidence interval (CI), and to explore the factors that affect the intention of dentists to recommend HPV vaccination. P-value <0.05 was considered statistically significant.
3. Results
As of July 25, 2020, a total 517 dentists had submitted the questionnaire and were included in the analysis. All dentists answered the 23 HPV-related knowledge questions. Notably, 465 dentists (89.94%) were unwilling to communicate with patients regarding HPV-related OPC and recommend HPV vaccination, whereas 506 dentists (97.87%) were willing to learn about HPV, HPV-related OPC and HPV vaccination. After the reliability analysis of the questionnaire, we considered α = 0.747 (α > 0.7) to be reliable.
3.1. Participant characteristics
A summary of the demographic characteristics of all participants is presented in . Of the 517 participants, a majority were female (58.41%), aged 20–29 years (43.71%), resident doctor (48.36%), bachelor degree (47.00%), married (66.54%), in public practice (74.47%) and in northern China (83.37%).
Table 1. Sociodemographic differences in mean total knowledge scores among dentists (n = 517)
3.2. Knowledge about HPV
The correct answer rate of the 23 knowledge items is shown in . Regarding HPV knowledge, a large percentage of the questions were incorrectly answered. In particular, 6 questions were correctly answered by less than a third of the participants. These questions were: “HPV related oropharyngeal cancer usually presents symptoms at an early stage” (14.84% correct); “There are more women than men in HPV related oropharyngeal cancer patients” (17.63% correct); “Men in mainland China are allowed to get HPV vaccine” (21.94% correct); “Genital warts are caused by the same HPV type(s) that cause oropharyngeal cancer” (28.17% correct); “People already infected with HPV are not allowed to get HPV vaccine” (29.89% correct); “The prognosis of HPV related oropharyngeal cancer is better than that of smoking and drinking” (32.26% correct).
Figure 1. Correct responses of HPV-related knowledge items (N = 517)
The mean and standard deviation (SD) of the total knowledge score was 14.25 ± 4.01 with a possible maximum score of 23. The relationship between the demographic characteristics of the participants and the mean total knowledge scores is shown in . There were statistically significant differences in the mean total scores of knowledge of participants by gender, age and title grade (p < .05). Male participants, aged 30–39 years and who where dentist-in-charge showed a relatively lower mean total knowledge score.
3.3. Intention to recommend HPV vaccination
shows the univariate analysis of whether dentists were willing to recommend HPV vaccination. There were statistically significant differences between the two groups in the four variables of mean total knowledge score, age, practice setting, and practice location (p < .05). Dentists who were unwilling to recommend HPV vaccination had significantly lower mean total knowledge scores than those who were willing to recommend (p < .001). Those aged 30–39 years showed the highest rate of unwillingness to recommend HPV vaccination while those practicing in private hospitals or Southern China had a higher rate of reluctance to recommend HPV vaccination.
Table 2. Univariate regression results between influencing factors and recommend HPV vaccination intention (n = 517)
To determine the correlation between the 3 demographic variables with differences in univariate analysis and the willingness to recommend HPV vaccination, we used a binary logistic regression model for data analysis. Results showed that the three variables of age, practice setting and practice location were significantly correlated with the willingness to recommend HPV vaccination (p < .05) (). Compared to dentists aged 20–29 years, the willingness of dentists aged between 30–39 years to recommend HPV vaccination decreased by 0.734 times (OR = 0.246, 95% CI: 0.119–0.509). Futhermore, the willingness to recommend HPV vaccination by dentists in private hospitals was 0.656 times lower than that of dentists in public hospitals (OR = 0.343, 95% CI: 0.182–0.650) while the willingness of dentists practicing in Northern China to recommend HPV vaccination was 2.795 times higher than that of those practicing in Southern China (OR = 2.795, 95% CI: 1.421–5.499).
Table 3. Multivariate regression results between influencing factors and recommend HPV vaccination intention
3.4. Barriers to recommending HPV vaccination
Fifty-two dentists (10.06%) were unwilling to educate patients about HPV-related OPC and recommend HPV vaccination. The main reason was “It is not within the scope of practice of dentists” (67.3%), followed by “I am worried about the quality and side effects of the vaccine” (57.7%) and “I do not want to communicate with patients on sexual topics” (51.9%) ().
Table 4. Barriers of recommended HPV vaccination
3.5. Ways to acquire knowledge
A total of 506 dentists (97.87%) were willing to learn about HPV, HPV-related OPC and HPV vaccination. The most popular mode preferred by dentists to acquire knowledge was through continuing with education courses (86.6%). More than half of the dentists preferred to obtain relevant knowledge from social media (66.8%) and oral health colleagues (56.5%). Dentists who preferred scholarly journals and other channels accounted for 47.0% and 17.0%, respectively ().
Table 5. Ways to acquire knowledge
4. Discussion
This was the first study to assess the knowledge possessed by dentists in China regarding HPV, HPV-related OPC and HPV vaccination, their willingness and barriers to discussing HPV infections with patients and recommend the HPV vaccine to eligible patients. We hope that this study will arouse the attention of Chinese dentists toward HPV-related OPC, play a role in data support, and promote the subsequent popularization of the HPV vaccine and primary prevention of HPV-related OPC.
After being informed of the fact that the HPV vaccine may play an important role in the primary prevention of HPV-related OPC, 89.94% of Chinese dentists were willing to discuss HPV-related OPC with patients and recommend HPV vaccination to eligible patients. The correct rates of the three questions: “The incubation period of the HPV is very short; HPV related oropharyngeal cancer usually presents symptoms at an early stage; People already infected with HPV are not allowed to get HPV vaccine” as answered by Chinese dentists were 49.13%, 14.51%, and 29.59%, respectively. These findings indicated that Chinese dentists have knowledge gaps regarding the onset time of HPV infections, the clinical characteristics of HPV-related OPC and the conditions for HPV vaccination. Moreover, their knowledge reserves have not yet reached the level that can create awareness on HPV-related OPC and encourage vaccination. Notably, the results of this survey are within our expectations. First, undergraduate education textbooks in China only describe the epidemiology, clinical characteristics and treatment of OPC, and no information has been published on HPV-related OPC. Besides, from the literature, we found that there were relatively few studies on the prevention and epidemiology of HPV-related OPC in the Chinese population.
In this survey, the average total knowledge score of dentists who were willing to recommend vaccination was higher than that of dentists who were unwilling to recommend vaccination. This implies that the more dentists have HPV-related knowledge, the more likely they are to recommend vaccination to patients. Furthermore, studies among pediatricians have documented that knowledge is the main motivation factor to recommend HPV vaccination.Citation32 The higher the level of knowledge about HPV and HPV vaccination, the easier it is for medical providers to discuss with patients the role of multiple sexual partners in HPV-related OPC and increase the possibility of recommending the vaccine to their patients’ children.Citation33 Notably, 97.87% of dentists in our study were willing to obtain relevant knowledge about HPV, HPV-related OPC and HPV vaccination. This implies that Chinese dentists are an important potential group to promote HPV vaccination. Continuing with education courses was found to be the most desirable way (86.6%) for dentists to acquired knowledge. Although social media was found to be another major option for dentists (66.8%), the knowledge on social media platforms and the Internet should be carefully screened. The above findings show that educational interventions should be used to improve the level of dentists’ knowledge on HPV, HPV-related OPC and HPV vaccination.
Studies have reported that appropriate interventions by medical providers can play a positive role in promoting HPV vaccination.Citation17 In the correlation analysis between the sociodemographic information of dentists and the mean total knowledge score, we found that males, aged 30–39 years and are dentist-in-charge had relatively lower knowledge scores. Additionally, dentists aged 30–39 years, working in private hospitals, and practicing in Southern China exhibited a lower willingness to recommend HPV vaccination. These related variables have important implications, and should be considered as areas of important educational focus and behavioral intervention for dentists in the future.
To increase the recommendation rate of dentists through targeted interventions, we conducted a barrier analysis on those who refused to recommend the vaccines. Among those who refused to recommed the vaccine, 67.31% believed that the recommendation of HPV vaccination was not within the scope of practice of dentists. Resolving this kind of professional conflict may require professional associations to issue some clear guidelines or policies to eliminate the concerns of dentists.
Moreover, 57.69% of rejecters in our study expressed concern about the quality and side effects of the vaccine. Currently, four HPV vaccines are approved for use in mainland China: the 2vHPV Cervarix and Cecolin, which are used to prevent HPV 16 and 18 infections; the 4vHPV Gardasil (HPV16, 18, 6 and 11); and the 9vHPV Gardasil 9 (HPV 16, 18, 6, 11, 31, 33, 45, 52 and 58). Clinical studies have reported that injection of Cervarix or Gardasil before exposure to HPV can provide 90% protection against cervical intraepithelial neoplasia and adenocarcinoma in situ.Citation34,Citation35 Gardasil 9 can effectively (>95%, vaccination before exposure to HPV) prevent pre-cancerous lesions and infections with few side effects.Citation36 China’s domestic vaccine Cecolin has similar efficacy to Cervarix, and no serious adverse events have been reported.Citation37 It has been proven that dentists strengthen their confidence in the quality and safety of the HPV vaccine after learning about the HPV vaccine after continuing with education courses.Citation17 Therefore, we believe that if sufficient educational interventions are provided to dentists, the views of some dentists who are unwilling to recommend vaccines may change.
Besides, 51.92% of the rejecters were not willing to discuss sexual topics with patients. This may be due to the relatively conservative sexual culture in China and the fear of complaints about sexual harassment by patients. Information acquired from American dentists, showed that poor communication with patients on sexual topics hinders the promotion of the HPV vaccine.Citation38,Citation39 Therefore, professional associations should train dentists on professional communication skills to enhance discussions on sexual topics.
It is worth noting that in our survey, only 21.47% of dentists knew that men were not allowed to receive the HPV vaccine in mainland China. In some developed countries, HPV vaccination is gender-insensitive. Currently, only women in mainland China can be administered with the HPV vaccine, and each vaccine has different age restrictions. Cervarix and Cecolin are registered for ages 9–45 years, Gardasil is for 20–45 years, while Gardasil 9 is for 16–26 years. A study based on the Chinese population reported that the prevalence of HPV infections among men is 10.5%.Citation40 Young men who had sex with men (MSM) formed the high-risk group of HPV infection, with a prevalence rate of as high as 37.5%.Citation41 Besides, a small sample study showed that the ratio of male to female patients with HPV-related OPC in China was about 4 to 1,Citation42 which is similar to that in other countries.Citation6,Citation43-45 However, only 16.83% of the dentists in our survey correctly believed that male patients in HPV-related OPC were more than female. Elsewhere, a study evaluating male college students’ willingness to get HPV vaccination in China showed that only 38.9% of college boys were willing to actively be vaccinated.Citation46 We hope that with the continuous in-depth studies on the prevention of HPV infection among Chinese men, the application and popularization of HPV vaccine among Chinese men will eventually be enhanced.
There are some limitations associated with this study. First, due to the limitations of investigators’ ability and research funding, the number of recruited dentists was small, this prompted us to use a convenient sampling method to adminster the questionnaire. The sample may not be a representative of all Chinese dentists. Secondly, the questionnaire was anonymous and self-filled, which may have made dentists provide some erroneous answers, therefore, result interpretation should becautious. Thirdly, there were some deficiencies in the content of the questionnaire, such as the lack of the optimal age to recommend the population to receive HPV vaccine, and the lack of some basic knowledge of HPV-related cancer prevention and screening.
5. Implications for practice
We believe that Chinese dentists can play an important role in the primary prevention of HPV-related OPC, therefore, we propose some interventions. First, professional associations should clarify the role of dentists in the prevention of HPV-related OPC and the recommendation of HPV vaccination. Second, professional associations need to conduct professional training for dentists. The training content should include: a) professional knowledge of HPV, HPV-related OPC and HPV vaccination; b) communication skills for dentists on HPV-related issues with patients. Finally, we hope that social media can enhance the promotion of HPV-related OPC and HPV vaccines, so that more people can realize the role of HPV vaccination in the primary prevention of HPV-related OPC.
6. Conclusion
In summary, Chinese dentists have insufficient knowledge regarding HPV, HPV-related OPC and HPV vaccination, however, they are eager to acquire relevant knowledge and communicate with patients about HPV-related OPC and vaccination. Therefore, after professional education and receiving behavioral interventions, Chinese dentists are expected to play an important role in the prevention of HPV-related OPC and the popularization of HPV vaccine.
Disclosure of Potential Conflict of Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Additional information
Funding
References
- Chaturvedi AK, Anderson WF, Lortet-Tieulent J, Curado MP, Ferlay J, Franceschi S, Rosenberg PS, Bray F, Gillison ML. Worldwide trends in incidence rates for oral cavity and oropharyngeal cancers. J clin oncol. 2013;31:4550–59. doi:10.1200/jco.2013.50.3870. PMID:24248688.
- Shield KD, Ferlay J, Jemal A, Sankaranarayanan R, Chaturvedi AK, Bray F, Soerjomataram I. The global incidence of lip, oral cavity, and pharyngeal cancers by subsite in 2012. CA Cancer J Clin. 2017;67:51–64. doi:10.3322/caac.21384. PMID:28076666.
- Chaturvedi AK, Engels EA, Anderson WF, Gillison ML. Incidence trends for human papillomavirus-related and -unrelated oral squamous cell carcinomas in the United States. J clin oncol. 2008;26:612–19. doi:10.1200/jco.2007.14.1713. PMID:18235120.
- Gillison ML, Chaturvedi AK, Anderson WF, Fakhry C. Epidemiology of human papillomavirus-positive head and neck squamous cell carcinoma. J clin oncol. 2015;33:3235–42. doi:10.1200/jco.2015.61.6995. PMID:26351338.
- Van Dyne EA, Henley SJ, Saraiya M, Thomas CC, Markowitz LE, Benard VB. Trends in human papillomavirus-associated cancers - United States, 1999-2015. MMWR Morb Mortal Wkly Rep. 2018;67:918–24. doi:10.15585/mmwr.mm6733a2. PMID:30138307.
- Senkomago V, Henley SJ, Thomas CC, Mix JM, Markowitz LE, Saraiya M. Human papillomavirus-attributable cancers - United States, 2012-2016. MMWR Morb Mortal Wkly Rep. 2019;68:724–28. doi:10.15585/mmwr.mm6833a3. PMID:31437140.
- Berman TA, Schiller JT. Human papillomavirus in cervical cancer and oropharyngeal cancer: one cause, two diseases. Cancer. 2017;123:2219–29. doi:10.1002/cncr.30588. PMID:28346680.
- Steinau M, Saraiya M, Goodman MT, Peters ES, Watson M, Cleveland JL, Lynch CF, Wilkinson EJ, Hernandez BY, Copeland G, et al. Human papillomavirus prevalence in oropharyngeal cancer before vaccine introduction, United States. Emerg Infect Dis. 2014;20:822–28. doi:10.3201/eid2005.131311. PMID:24751181.
- Hirth JM, Chang M, Resto VA. Prevalence of oral human papillomavirus by vaccination status among young adults (18-30years old). Vaccine. 2017;35:3446–51. doi:10.1016/j.vaccine.2017.05.025. PMID:28526331.
- Pinto LA, Kemp TJ, Torres BN, Isaacs-Soriano K, Ingles D, Abrahamsen M, Pan Y, Lazcano-Ponce E, Salmeron J, Giuliano AR, et al. Quadrivalent Human Papillomavirus (HPV) vaccine induces HPV-specific antibodies in the oral cavity: results from the mid-adult male vaccine trial. J Infect Dis. 2016;214:1276–83. doi:10.1093/infdis/jiw359. PMID:27511896.
- Chaturvedi AK, Graubard BI, Broutian T, Pickard RKL, Tong ZY, Xiao W, Kahle L, Gillison ML. Effect of Prophylactic Human Papillomavirus (HPV) vaccination on oral HPV infections among young adults in the United States. J Clin Oncol. 2018;36:262–67. doi:10.1200/jco.2017.75.0141. PMID:29182497.
- Herrero R, Quint W, Hildesheim A, Gonzalez P, Struijk L, Katki HA, Porras C, Schiffman M, Rodriguez AC, Solomon D, et al. Reduced prevalence of oral human papillomavirus (HPV) 4 years after bivalent HPV vaccination in a randomized clinical trial in Costa Rica. PloS One. 2013;8:e68329. doi:10.1371/journal.pone.0068329. PMID:23873171.
- American Dental Association. Cancer prevention through HPV vaccination: an action guide for dental health care providers. Chicago (IL); 2018 [accessed 2020 Aug 27]. https://ebd.ada.org/~/media/ebd/files/dental-action-guide-web_ada.pdf?la=en.
- American Dental Association. Statement on human papillomavirus and squamous cell cancers of the oropharynx. Chicago (IL); 2012 [accessed 2020 Aug 25]. http://www.ada.org/1749.aspx.
- Walker KK, Jackson RD, Sommariva S, Neelamegam M, Desch J. USA dental health providers’ role in HPV vaccine communication and HPV-OPC protection: a systematic review. Hum Vaccine Immunother. 2019;15:1863–69. doi:10.1080/21645515.2018.1558690. PMID:30620632.
- Stull CL, Lunos S. Knowledge, attitudes and practices regarding human papilloma virus communication and vaccine advocacy among minnesota dentists and dental hygienists. J Dent Hyg. 2019;93:33–42. PMID:30819844.
- Shukla A, Nyambose J, Vanucci R, Johnson LB, Welch K, Lind E, Villa A. Evaluating the effectiveness of human papillomavirus educational intervention among oral health professionals. J Cancer Educ. 2019;34:890–96. doi:10.1007/s13187-018-1391-z. PMID:30006799.
- Zhao F, Qiao Y. Cervical cancer prevention in China: a key to cancer control. Lancet (London, England). 2019;393:969–70. doi:10.1016/s0140-6736(18)32849-6. PMID:30860036.
- Liu J, Yang XL, Zhang SW, Zhu LP, Chen WQ. Incidence, mortality, and temporal patterns of oropharyngeal cancer in China: a population-based study. Cancer Commun (London, England). 2018;38:75. doi:10.1186/s40880-018-0345-5. PMID:30594248.
- Zhang LW, Li J, Cong X, Hu XS, Li D, Wu LL, Hua H, Yu G-Y, Kerr AR. Incidence and mortality trends in oral and oropharyngeal cancers in China, 2005-2013. Cancer Epidemiol. 2018;57:120–26. doi:10.1016/j.canep.2018.10.014. PMID:30396144.
- Lam EW, Chan JY, Chan AB, Ng CS, Lo ST, Lam VS, Chan MMH, Ngai CM, Vlantis AC, Ma RKH, et al. Prevalence, clinicopathological characteristics, and outcome of human papillomavirus-associated oropharyngeal cancer in Southern Chinese patients. Cancer Epidemiol Biomarkers Prev. 2016;25:165–73. doi:10.1158/1055-9965.EPI-15-0869. PMID:26604268.
- Wang Z, Xia RH, Ye DX, Human Papillomavirus LJ. 16 infection and TP53 mutation: two distinct pathogeneses for oropharyngeal squamous cell carcinoma in an Eastern Chinese population. PloS One. 2016;11:e0164491. doi:10.1371/journal.pone.0164491. PMID:27749915.
- Guo L, Yang F, Yin Y, Liu S, Li P, Zhang X, Chen D, Liu Y, Wang J, Wang K, et al. Prevalence of human papillomavirus type-16 in head and neck cancer among the Chinese population: a meta-analysis. Front Oncol. 2018;8:619. doi:10.3389/fonc.2018.00619. PMID:30619756.
- Hu S, Xu X, Zhang Y, Liu Y, Yang C, Wang Y, Wang Y, Yu Y, Hong Y, Zhang X, et al. A nationwide post-marketing survey of knowledge, attitude and practice toward human papillomavirus vaccine in general population: implications for vaccine roll-out in mainland China. Vaccine. 2021;39:35–44. doi:10.1016/j.vaccine.2020.11.029. PMID:33243631.
- Sipp D, Frazer IH, Rasko JEJ. No Vacillation on HPV Vaccination. Cell. 2018;172:1163–67. doi:10.1016/j.cell.2018.02.045. PMID:29522737.
- Liu DL, Xie YF, Shu R. Statistical analysis of current oral health care and dental education resources in China. Chin J Dent Res. 2019;22:37–43. doi:10.3290/j.cjdr.a41773. PMID:30746531.
- Qin S, Fu JX, Chen MZ, Meng YT, Xu C, Luo Y. Acceptability of vaccination against human papillomavirus among women aged 20 to 45 in rural Hunan Province, China: a cross-sectional study. Vaccine. 2020;38:4732–39. doi:10.1016/j.vaccine.2020.05.017. PMID:32471777.
- Chuang SL, Su WW, Chen SL, Yen AM, Wang CP, Fann JC, Chiu SYH, Lee Y-C, Chiu H-M, Chang D-C, et al. Population-based screening program for reducing oral cancer mortality in 2,334,299 Taiwanese cigarette smokers and/or betel quid chewers. Cancer. 2017;123:1597–609. doi:10.1002/cncr.30517. PMID:28055109.
- Rutkoski H, Tay DL, Dixon BL, Pinzon LM, Mooney R, Winkler JR, Kepka D. A multi-state evaluation of oral health students’ knowledge of human papillomavirus-related oropharyngeal cancer and HPV vaccination. Journal of Cancer Education : The Official Journal of the American Association for Cancer Education. 2020;35:1017–25. doi:10.1007/s13187-019-01561-y. PMID:31222578.
- Lin Y, Lin Z, He F, Chen H, Lin X, Zimet GD, Alias H, He S, Hu Z, Wong LP, et al. HPV vaccination intent and willingness to pay for 2-,4-, and 9-valent HPV vaccines: a study of adult women aged 27-45 years in China. Vaccine. 2020;38:3021–30. doi:10.1016/j.vaccine.2020.02.042. PMID:32127227.
- Daley EM, Thompson EL, Vamos CA, Griner SB, Vazquez-Otero C, Best AL, Kline NS, Merrell LK. HPV-related knowledge among dentists and dental hygienists. J Cancer Educ. 2018;33:901–06. doi:10.1007/s13187-016-1156-5. PMID:28039675.
- Kahn JA, Rosenthal SL, Tissot AM, Bernstein DI, Wetzel C, Zimet GD. Factors influencing pediatricians’ intention to recommend human papillomavirus vaccines. Ambulatory Pediatr. 2007;7:367–73. doi:10.1016/j.ambp.2007.05.010. PMID:17870645.
- Hosking YP, Cappelli D, Donly K, HPV RS. Vaccination and the role of the pediatric dentist: survey of graduate program directors. Pediatr Dent. 2017;39:383–89. PMID:29070161.
- Lehtinen M, Paavonen J, Wheeler CM, Jaisamrarn U, Garland SM, Castellsagué X, Skinner SR, Apter D, Naud P, Salmerón J, et al. Overall efficacy of HPV-16/18 AS04-adjuvanted vaccine against grade 3 or greater cervical intraepithelial neoplasia: 4-year end-of-study analysis of the randomised, double-blind PATRICIA trial. Lancet Oncol. 2012;13:89–99. doi:10.1016/S1470-2045(11)70286-8. PMID:22075171.
- Garland SM, Hernandez-Avila M, Wheeler CM, Perez G, Harper DM, Leodolter S, Tang GW, Ferris DG, Steben M, Bryan J, et al. Quadrivalent vaccine against human papillomavirus to prevent anogenital diseases. N Engl J Med. 2007;356:1928–43. doi:10.1056/NEJMoa061760. PMID:17494926.
- Joura EA, Giuliano AR, Iversen OE, Bouchard C, Mao C, Mehlsen J, Moreira ED, Jr.Ngan Y, Petersen LK, Lazcano-Ponce E, et al. A 9-valent HPV vaccine against infection and intraepithelial neoplasia in women. N Engl J Med. 2015;372:711–23. doi:10.1056/NEJMoa1405044. PMID:25693011.
- Qiao YL, Wu T, Li RC, Hu YM, Wei LH, Li CG, Chen W, Huang SJ, Zhao FH, Li MQ, et al. Efficacy, safety, and immunogenicity of an escherichia coli-produced bivalent human papillomavirus vaccine: an interim analysis of a randomized clinical trial. J Natl Cancer Inst. 2020;112:145–53. doi:10.1093/jnci/djz074. PMID:31086947.
- Vázquez-Otero C, Vamos CA, Thompson EL, Merrell LK, Griner SB, Kline NS, Catalanotto FA, Giuliano AR, Daley EM. Assessing dentists’ human papillomavirus-related health literacy for oropharyngeal cancer prevention. J Am Dent Assoc (1939). 2018;149:9–17. doi:10.1016/j.adaj.2017.08.021. PMID:29031503.
- Daley E, Dodd V, DeBate R, Vamos C, Wheldon C, Kline N, Smith S, Chandler R, Dyer K, Helmy H, et al. Prevention of HPV-related oral cancer: assessing dentists’ readiness. Public Health. 2014;128:231–38. doi:10.1016/j.puhe.2013.12.002. PMID:24602857.
- Wei F, Yin K, Wu X, Lan J, Huang S, Sheng W, Zhao J, Su Y, Wang Y, Li Y, et al. Human papillomavirus prevalence and associated factors in women and men in south China: a population-based study. Emerging Microbes Infect. 2016;5:e119. doi:10.1038/emi.2016.118. PMID:27876782.
- Fan S, Li P, Ouyang L, Yuan T, Gong H, Ding Y, Luo Z, Wu G, Yu M. Anal human papillomavirus infection among MSM attending university in China: implications for vaccination. Vaccines (Basel). 2020;8. doi:10.3390/vaccines8020175. PMID:32283842.
- Xu S, Sun B, Zhou R, Shi C, Han Y, Li J, Sun J, Tian Z, Zhang Z, Li J, et al. Evaluation of p16 as a surrogate marker for transcriptionally active human papillomavirus status of oropharyngeal squamous cell carcinoma in an eastern Chinese population. Oral Surg Oral Med Oral Pathol Oral Radiol. 2020;129:236–45.e2. doi:10.1016/j.oooo.2019.11.008. PMID:31987673.
- de Martel C, Plummer M, Vignat J, Franceschi S. Worldwide burden of cancer attributable to HPV by site, country and HPV type. Int J Cancer. 2017;141:664–70. doi:10.1002/ijc.30716. PMID:28369882.
- Hartwig S, St Guily JL, Dominiak-Felden G, Alemany L, de Sanjosé S. Estimation of the overall burden of cancers, precancerous lesions, and genital warts attributable to 9-valent HPV vaccine types in women and men in Europe. Infect Agent Cancer. 2017;12:19. doi:10.1186/s13027-017-0129-6. PMID:28400857.
- Buttmann-Schweiger N, Deleré Y, Klug SJ, Kraywinkel K. Cancer incidence in Germany attributable to human papillomavirus in 2013. BMC Cancer. 2017;17:682. doi:10.1186/s12885-017-3678-6. PMID:29037233.
- Wang S, Han B, Wan Y, Liu J, Zhao T, Liu H, Cui F. Do male university students know enough about Human Papillomavirus (HPV) to make informed decisions about vaccination? Med Sci Monit. 2020;26:e924840. doi:10.12659/msm.924840. PMID:32603317.