HPV prevalence and genotype distribution in Liaocheng men between 2016 and 2022
Lili Zheng1, * , Jieyu Qi 2, Liyuan Zheng3, Shuangfeng Chen1, Wenhui liu4, * , and Ke Li1, *
1Central Laboratory of Liaocheng Peoples’ Hospital, Liaocheng, 252000, Shandong, China;
2 Clinical Laboratory of Liaocheng Peoples’ Hospital, Liaocheng, 252000, Shandong, China;
3School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, 266071, Shandong, China;
4Department of dermatology Liaocheng Peoples’ Hospital, Liaocheng, 252000, Shandong, China;
*Correspondence: Ke Li, 2385677237@qq.com; Wenhui liu, 215197617@qq.com; Lili Zheng,lily20060306@126.com* Contributed equally to this work.

ABSTRACT

HPV infection can lead to HPV-related cancer in men, including the anus, penile, and oropharyngeal cancers and precancerous lesions. This study retrospectively investigated HPV prevalence and genotype distribution in Liaocheng men between 2016 and 2022. The total HPV positive rate was 64.87% (2388/3681, 95% CI: 63.32%-66.40%), where HR-HPV and LR-HPV accounted for 42.49% (1564/3681, 95% CI: 40.90%-44.09%) and 69.71% (2566/3681, 95% CI: 68.20%-71.17%), respectively. The mixed HPV infection rate of two and more genotypes was 35.72%. The infection rate of HR-HPV increased with the number of positive cases annually from 2016 (16.91%) to 2022 (46.59%). The most common HR-HPV genotypes were HPV16 (11.60%), HPV52 (6.95%), and HPV59 (6.28%), whereas the least common HR-HPV was HPV26. The most common LR-HPV genotypes were HPV6 (56.99%), HPV11 (23.79%), and HPV43(6.37%). The 9v HPV vaccine preventable for LR-HPV and HR-HPV accounted for 80.78% and 30.40%, respectively, in this study. Most HPV-positive patients aged 1-86 were in the 30-39 age group. This study confirmed that HPV prevalence in Liaocheng men was common and diverse. HPV16, HPV52, and HPV59 are widely distributed in Liaocheng men, and the male HR-HPV infection rate remained high in this region. Regarding public health and cancer prevention, it is recommended and effective to include the HPV vaccination in the national vaccination program for men.

KEYWORDS

Human papillomavirus, Male, Prevalence, Penile Neoplasms/virology, Vaccine

1. INTRODUCTION

Human papillomavirus (HPV) is a common sexually transmitted virus [1]. It can also be transmitted nonsexually through horizontal (fomites, fingers, mouth, and skin contact) and vertical (mother-to-child) routes [2]. The global HPV infection rate among males (3.5%-45%) was similar to that among women (2%-44%) [3]. The incidence ratio for infection transmission was also similar, 0.59 (95% CI, 0.16-2.20) for male-to-female transmission and 0.77 (95% CI, 0.37-1.60) for female-to-male transmission [4]. HPV-attributable cancer predominated in women [5]. However, HPV-attributable cancer in men cannot be ignored, including anal, penile, and oropharyngeal cancers [6-8] and certain tumor tissues [9], such as finger multiple invasive squamous cell carcinomas [10]. A large proportion of penile cancers and penile intraepithelial neoplasias are associated with HPV DNA infection [11]. HPV infection is responsible for 50.8% of penile cancers globally, 79.8% of penile intraepithelial neoplasia, and 90% genital warts [12]. Even Germany launched a campaign: HPV prevention is man’s business [13].
Approximately 450 kinds of HPV have been isolated and sequenced to date [14]. HR-HPV is generally considered to be an oncogenic HPV type. The most frequent cancer-causing HR-HPV genotypes are HPV16, HPV18, HPV31, HPV33, HPV35, HPV39, HPV45, HPV51, HPV52, HPV56, HPV58, and HPV59, which are frequently associated with penile cancer [15, 16]. The second most frequent genotype associated with potential carcinogenicity is HPV68, and several other HR-HPV types (HPV26, HPV53, HPV66, HPV67, HPV70, HPV73, HPV82, HPV30, HPV34, HPV69, HPV85, and HPV97) have been thought to be potentially carcinogenic [17]. HR-HPV and LR-HPV are different in promoter localization, promoter regulation, and messenger RNA splicing patterns, and these differences affect the expression of E6/E7 genes [18]. LR-HPV cause benign and localized lesions but can also cause cancer in certain conditions, such as severe combined immunodeficiency and epidermohypoplasia verruciformis (EDV) [19]. Persistent LR-HPV infection can also lead to complex diseases, such as recurrent respiratory papilloma, for which the management and treatment impose a considerable socioeconomic burden [20]. HPV epidemiology varied by race/ethnicity, age at first sexual intercourse, city/urban residence, and sex life [21]. The HPV vaccination rates differed in men because of gender and social background factors [22]. The male HPV infection status of Liaocheng (China) has not been reported as of yet. The city of Liaocheng is located on the border of the Hebei-Shandong-Henan provinces and is a densely populated regional medical center of Shandong Province. Understanding the ecological diversity of HPV prevalence and genotype distribution in men at different times and locations is crucial for optimizing HPV vaccination and maximizing vaccination efficacy.

2. MATERIALS AND METHODS

2.1 Ethical consideration

The present study was approved by the Ethics Committee of LiaoCheng People’s Hospital with approval number 2023004. No informed consent or other action from the patients was required because of the anonymity of the data analyses. All experiments followed the laboratory biosafety guidelines in a lab certified by the National Center for Clinical Laboratories.

2.2 Sample collection

The study retrospectively analyzed male patient samples collected between January 201 and December 2022 from the Liaocheng People’s Hospital dermatology clinic. The analyses included urinary tract infection (UTI), genital warts, condyloma, balanitis, penis neoplasm, and eczema. The samples were obtained by gently rubbing saline-soaked nylon tips around the penile squamous areas, including the shaft and glans. The samples were suspended using a mixing tip into a tube containing 1 mL of physiological saline and stored at 4°C until use.

2.3 HPV DNA amplification and genotyping

HPV positivity was identified using polymerase chain reaction (PCR), and the HPV PCR-flow fluorescence assay was used for HPV genotyping. Twenty-seven HPV genotypes were tested using the Nucleic Acid genotyping Kit for Human Papillomavirus (Tellgen, China), including 17 HR-HPVs (HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 26, 53, 68, and 82) and 10 LR-HPVs (HPV6, 11, 40, 42, 43, 44, 55, 61, 81, and 83).

2.4 Data analysis

All data were analyzed using the SPSS17.0 statistical software (SPSS, IBM, USA). The chi-square test was used to compare the infection rates of different groups; statistical significance was tested at P < 0.05. Positive predictive value with 95% confidence intervals (CIs) was calculated using the binomial distribution.

3. RESULTS

3.1 HPV prevalence in 3681 males

Between 2016 and 2022, 3681 males were enrolled at the Liaocheng People’s Hospital. As shown in Figure 1a, the total positive rate of HPV was 64.87% (2388/3681, 95% CI: 63.32%-66.40%), where HR-HPV and LR-HPV accounted for 42.49% (1564/3681, 95% CI: 40.90%-44.09%) and 69.71% (2566/3681, 95% CI: 68.20%-71.17%), respectively. Table 1 presents the clinical diagnosis data of 2388 HPV-positive males. Most HPV-positive patients exhibited symptoms, such as a penis-genital wart, common wart, urethritis, dermatitis, and rash. Only a few males were examined physically (9.92%), and penis-genital wart accounted for 45.48%, higher than other diagnostic types (Table 1).
As shown in Figure 1b, the single infection rate was 64.28%, and the mixed infection rate of two and above genotypes was 35.72%. The double infection rate was 22.71%, followed by the trebling infection (8.92%), quadruple infection (2.55%), and other multiple infections (1.51%). Priority was given to the single and double infection rates over other kinds of mixed infection (P < 0.01).

3.2 HPV prevalence between 2016 and 2022

From 2016 to 2022, as the number of male patients tested for HPV increased, the prevalence of HPV-positive patients each year was analyzed. As shown in Figure 3, the number of positive males increased annually, and the overall positive detection rate was 39.7%–77.6%. The two relatively low positive rates were 39.7% and 59.4% in 2016 and 2022, respectively. The highest infection rate appeared in 2017 (77.59%). In each year between 2018 and 2021, there was no significant difference in the positive rate for each HPV type (x2 = 5.25, P = 0.26). The annual infection rate of each HPV type was further analyzed (Table 2). The infection rate of HR-HPV increased annually (Figure 3) from 2016 (16.91%) to 2022 (46.59%) (P < 0.01,x2= 20.33, P = 6.5e-6) (Table 2). The LR-HPV infection rate increased significantly from 2016 (37.50%) to 2020 (85.82%) (P <0.01,x2 = 49.38, P = 2.1e-12), then decreased in 2021 (74.59%) and 2022 (59.13%) (P < 0.01, x2=5.39, P = 0.02).

3.3 HPV genotype distribution among 2388 HPV-positive patients

Seventeen HR-HPV and ten LR-HPV genotypes were retrospectively analyzed from the HPV-positive patients (n = 2388). As evident from Table 3, LR-HPV6, LR-HPV11, and HR-HPV16 were the major infection types in this study. The top ten HR-HPV genotypes are as follows in descending order: HPV16 (11.60%), HPV 52 (6.95%), HPV59 (6.28%), HPV66 (5.36%), HPV56 (5.23%), HPV39 (5.07%), HPV58 (4.27%), HPV51 (4.15%), HPV53 (4.19%), and HPV18 (4.02%). There was no significant difference among the top ten HR-HPV types (x2 = 5.24, P = 0.26), and the least prevalent HR-HPV type was HPV26 (0.17%). The most common LR-HPV genotypes were HPV 6 (56.99%), HPV 11 (23.79%), HPV 61 (6.37%), and HPV 43 (6.28%); the least LR-HPV was HPV 83 (0.54%).
As shown in Table 2, the primary benefit of each infection type annually varied slightly. The distribution of common HPV genotypes in 2016-2022 was further analyzed in Figure 4. A subsequent analysis was performed from 2017 because of the low reliability caused by the small amount of data (Samples < 100) in 2016. The prevalence of total HR-HPV genotypes increased from 2017 (16.91%) to 2022 (46.95%) (Figure 4a). Among the HR-HPV genotypes, the prevalence of HPV 52 increased from 2017 (0.70%) to 2022 (10.47%). The prevalence of total LR-HPV genotypes increased from 2017 (67.76%) to 2022 (85.82%), which was higher than that of total HR-HPV genotypes (Figure 4b). The infection rate of HPV6 increased from 2017 (47.18%) to 2022 (63.11%), and that of HPV11 increased from 2017 (16.89%) to 2022 (32.62%) (Table 2).

3.4. Analysis of the prevalence of 9-valent HPV vaccine targeting genotypes.

The currently approved 9-valent HPV vaccine (9v HPV vaccine) is the highest potency vaccine, which contains LR-HPV (HPV 6 and 11) and HR-HPV (HPV 16, 18, 31, 33, 45, 52, and 58). The prevalence of 9v HPV vaccine targeting genotypes was analyzed (Figure 5), where the 9v vaccine preventable for LR-HPV and HR-HPV accounted for 80.78% and 30.40%, respectively. The detailed prevalence of these nine genotypes of HPV was analyzed. As shown in Table 3, in addition to HPV 16 (11.6%), the prevalence of three other vaccine targeting types—HPV31 (1.34%), HPV33 (1.13%), and HPV45 (1.09%)—was extremely low. Notably, 69.60% of HR-HPV types (for instance, the main genotypes HPV52, HPV59, HPV66, HPV56, and HPV39) were not included in the 9v HPV vaccine protecting range.

3.5 Age Distribution in 2388 HPV positive patients

As shown in Figure 6, 2388 HPV-positive patients ranged from 1 to 86 years old, with a mean age of 34.23 (SD = 12.49). The number of HPV-positive males in the <20 age group was the lowest (7.20%), and the youngest was 1. The number of HPV-positive males in the 30-39 age group was the highest (34.09%) among all age groups, followed by the 20-29 age group (28.52%). There were no significant differences between the 20-29 and 30-39 age groups (P> 0.05, x2 = 0.72, P = 0.40). The positive rate decreased as the age of the >40 age group increased. Among them, the 40-49 age group accounted for 17.38%, the 50-59 age group accounted for 8.12%, and the >60 age group was the least (4.69%).

4. DISCUSSION

In this study, we reported the prevalence and genotype distribution of HPV infection in men who visited Liaocheng People Hospital with STI (sexually transmitted infection) symptoms between 2016 to 2022, and the total positive rate of HPV was 64.87%. The prevalence of HPV among men varied between countries and crowds. The male HPV infection rates in Czech, Brazil, and Hong Kong were 96.8%, 80%, and 90%, respectively [23-25], which were higher than that mentioned in our study. Furthermore, the infec­tion rates of any genital HPV type in men were in Brazil (60.2%), Mexico (49.2%), and the United States (46.9%) [26]. In 2014, 9% of healthy men from Africa, the United States, Asia, and Europe were HPV carriers [27]. In China, the average anal HPV positivity rate of any genotype among MSM (men who have sex with men) was 62.1% [28], and it varied by region, for instance, Shanghai (65.5%) [29], Qingyuan area of Guangzhou (54.3%) [30], and Beijing (50.9%) [31]. The HPV prevalence of our study (64.87%) was similar to that of Shanghai and higher than the average of China [28, 30]. In our study, the prevalence of HR-HPV and LR-HPV accounted for 42.28% and 72.32%, respectively, higher than Shanghai (28.0% and 57.6%, respectively) [30].
Various mixed infections related to the degree of pathological changes were further analyzed, with most single infections accounting for 64.28%, nearly double the rate of 35.72% for mixed infections. The rate of two or more mixed infections decreased with the increase in HPV type. In Japan, a single HPV-type infection was found in the urinary tract (89%) [32]. The multiple infection rate was 42.9% in Vietnam males [33]. In our study, the two or more mixed infection rate was 35.72%, higher than in Shanghai (25.8%) [25]. A high rate of multiple infections may be associated with the risk of cervical cancer in women [34], whereas men are likely to be infected with multiple HPV strains [35].
Genotype distribution of HPV infection in males differs among countries. Between 1995 and 2009, the five most prevalent types worldwide were HPV16, HPV18, HPV52, HPV31, and HPV58 [36]. Similar to our result, HPV16 was the most prevalent HR-HPV type in the Czech [23], Vietnam [33], and Japan [32]. In Shanghai, China, HPV16, HPV59, and HPV52 were the most popular HR-HPVs, whereas the three most frequent LR-HPVs were HPV6, HPV11, and HPV43 [30]. This result is consistent with our result of the top three common HR-HPV genotypes (HPV16, HPV52, and HPV59) and the top three LR-HPV genotypes (HPV6, HPV11, and HPV43). HPV6 and HPV11 are more commonly related to the carcinogenesis of condylomatous lesions and cause 90% of all external genital warts [37, 38]. The high positive rates of HPV6 and HPV11 in our study could be because most male patients had inflammation and warts. Moreover, the most prevalent genotypes differed between males and females in this region, especially HPV-59 was more prevalent in males (6.28%) than in females (2.09%) [39], and a similar difference is also reported in Lebanon, where HPV-59 prevalence was higher in men (6.6%) than in women (2.1%) [35]. Moreover, each year’s analysis revealed that the infection rate of HR-HPV increased annually, especially HPV52, so HR-HPV infection in LiaoCheng men cannot be ignored.
The 9v HPV vaccine (Gardasil 9TM) has been proven to protect against seven HR-HPV (HPV16, 18, 31, 33, 45, 52, and 58) and two LR-HPV genotypes (HPV6 and 11) infections. A widespread 9v HPV vaccination program and early vaccination were supported by clinical studies [40]. Chinese clinical studies have confirmed that HPV vaccines for women are highly effective and safe [41]. Based on the prevalence of vaccine-protected genotypes, it can be predicted that the 9v HPV vaccine can effectively prevent 80% LR-HPV and 30% HR-HPV infections in LiaoCheng males. However, 69.60% of HR-HPV types were not protected by the 9v HPV vaccines, especially the prevalence of the top genotypes (HPV59, HPV66, HPV56, HPV39, HPV51, and HPV53) in this region. Therefore, these HR-HPV genotypes should be prioritized in future vaccine optimization.
In our study, HPV prevalence was highest in the 30-39 (34.09%) and 20-29 (28.52%) age groups and decreased in the >40 age group. These findings are similar to the age distribution of Vietnamese male patients, with the highest HPV infection rate in the 20-39 age group, and the rate decreased in the >40 age group [33]. Notably, children also have HPV infection risk through the placenta, the amniotic fluid, or via contact with maternal genital mucosa during natural birth [2]. Our study’s age analysis revealed that those under 20 were mainly composed of those aged 15 to 19, including each aged 1, 5, 6, and 9. Generally, males in early adulthood are deemed too old to be vaccinated against HPV, although studies have suggested that HPV infection rates are not correlated with male age [40, 41]. In Germany, neutral HPV vaccination is recommended for all children aged 9 to 14 years to prevent HPV-related diseases [13]. Given that four children were found to be HPV carriers in our study, we must recommend vaccination for male children in this area.

5. CONCLUSION

The present study demonstrated the HPV prevalence and the genotype distribution in Liaocheng men. It is essential to know the prevalence of HPV infection in Shandong Liaocheng and serves as a supplement to the data on HPV infection in women, consistent with the current prevalence of HPV in China. In addition to HPV16 and HPV52, the prevalence of HPV59, HPV66, HPV56, HPV39, HPV58, HPV51, HPV53, and HPV18 was also high in this region. This study indicated the urgent need for enhanced HPV prevention and control measures in the male population, which is crucial in optimizing and advancing vaccine research.