China has a vast territory and a large population of more than 1.4 billion. The prevalence of HPV varied greatly in different provinces of China. There have been some studies reported the prevalence and genotype distribution of HPV in different provinces in China[10, 11, 12, 13]. However, there are few reports on HPV prevalence in Henan Province. The present study provided the prevalence and genotype data of HPV from women attending regular gynecological outpatient clinic from January 2018 to December 2019 in northern Henan province of China. Our study showed that the overall HPV infection rate was 19.7%, which was similar to the results from several surveys of HPV prevalence that reported in other provinces of China[14, 15, 16]. The prevalence of HPV in northern Henan province was lower than that reported in Shandong Province (28.4%) and Fujian Province(38.3%)[17, 18], but higher than Yunnan Province (12.9%) and Shanxi Province (8.92%)[10, 19]. The different HPV prevalence in northern Henan Province was expected to be explained by the different economic conditions, different living habits and customs, cultural diversity, sampling strategy, as well as the HPV detection methods. According to the previous reports, the HPV infection rates ranged from 6.7–44.5% in China. Although the HPV infection rates in northern Henan Province was not the highest in China, more attention should be paid to the women infected with HPV.
This present study provided age-specific HPV infection rates among women. Our results showed than women under 20 years, with the overall infection rate of 41.8%, had the highest infection rate in the six designed groups. The single HPV infection rate, the double HPV infection rate and the multiple HPV infection rate were also the highest in women under 20 years. There are two possible reasons for this phenomenon: one reason is that compared with other groups, the total number of women under 20 years participating in the survey is relatively small. Healthy women under 20 years undergoing normal medical examinations were rarely required to be tested for HPV. Most of them were outpatients and they come to hospital for some medical problems, leading to the high prevalence of HPV. Another reason is that the young women are sexually active and they don’t know how to protect themselves, which makes them sensitive to HPV infection. The above two reasons led to the highest infection rate in G1 group. It was reported that young women infected with HPV were temporary, and the virus would be cleared by the immune system in most of the cases[21, 22]. Therefore, the infection rate of HPV will gradually decline with the age increased. In the present study, the prevalence of HPV declined gradually in the middle-aged groups, and slightly increased in G6 group (22.9%), which indicated that women over 60 years suffered severely from HPV infection. For women over 60 years, their immune system function gradually decreased, therefore, they become susceptible to HPV infection. If the HPV cannot be eliminated by the immune system and persist for several years, this will represent a risk factor for neoplasia development. HPV infection rates ranged from 17.7–21.1% among women in groups G2 to G5. Since HPV infection is a major etiological factor for the cervical cancer development, the high prevalence rate of HPV indicated the significant burden of cervical cancer in Henan Province. It is a pity that despite we can detect the HPV infection, there is no medical treatment to eliminate HPV infection. Future treatment that could eliminate HPV infection and prevent progression of cervical cancer is of great interest.
Our present study also provided the age-specific distribution of single, double and multiple HPV infection rates. Except the G1 group, the single, double and multiple HPV infection rates of the rest groups were very close. Up to now, there has not been reached an agreement that whether multiple HPV infections increase the risk of cervical cancer than single HPV infection. Some studies have reported that multiple HPV infections had a higher risk with the occurrence and development of cervical cancer than single HPV infections[23, 24]. However, other studies have found that single HPV infections had a greater risk of developing cervical cancer with respect to multiple infections[25, 26]. In our study, the prevalence of single HPV infections is high, accounted for 13.7% of the total cases, and HPV16 was the most commonly detected genotype in single HPV infection. HPV16 infection is the one with the highest oncogenic risk. Thus, more attention should be paid to single HPV16 infection. The double HPV infection and multiple HPV infection accounted for 4.3% and 1.8% of the total cases, respectively. The investigation of double and multiple HPV is of great importance to study the prevalence of HPV and is also of great significance to develop multivalent HPV vaccine.
It is important to know the HPV genotypes distribution since data concerning the distribution of HPV genotypes is concerning with the vaccine development. Persistent infection with HR-HPV is the primary etiological factor for cervical cancer. There is up to 70% of cervical cancers caused by HPV16 and HPV18, with the remainder of cervical cancers caused by other HR-HPV genotypes. In the present study, the HPV16, HPV52, HPV58, HPV53 and HPV39 were the top five HR-HPV genotypes. HPV16 ranked first in our study and the infection rate reached up to 4.3%. HPV52 and HPV58 ranked second and third respectively. Compared with HPV16, both HPV52 and HPV58 had a lower correlation with cervical cancer. The top three genotypes distribution pattern is consistently with the data from several previous Chinese population-based HPV investigations [17, 27, 28]. It was reported HPV18 ranked second in Chinese women between 1991 and 2016. In our report, HPV18 with an infection rate of 1.1%, ranked seven in the HR-HPV genotypes in the study, which was consistent with the recent results in several other regions in China[17, 19, 29].
What’s more, the study also investigated the distribution of LR-HPV. Our study showed that the top five most common LR-HPV genotypes were HPV6, HPV61, HPV81, HPV54 and HPV11. For the LR-HPV types, cervical cancer association is very rate in the general women population. LR-HPV mainly cause genital warts, common warts, flats warts and many other skin lesions, which are usually asymptomatic but are sometimes accompanied by inching, burning or bleeding, leading to psychosocial disturbances. To date, the 9-valent HPV vaccine is used in the prevention of infection with HPV6, HPV11, HPV16, HPV18, HPV31, HPV33, HPV45, HPV52 and HPV58. Our results support the recommendation of the 9-valent HPV vaccine for routine vaccination in northern Henan Province. Meanwhile, vaccine against HPV53, HPV39 and HPV51 should also be developed for the women in this area.
The present investigation provided the recent data on the prevalence and genotype distribution of HPV in northern Henan Province, however, limitations existed. One limitation is that the relationship between the incidence of cervical cancer and the different HPV genotypes infection were not collected in this study. Another limitation is that the viral load in the enrolled individuals were not detected. It has been reported that both HPV genotype and viral load in combination show promise for predicting the development of cervical cancer in HPV positive women. In the future, the role of different HPV genotypes infection and viral load on the risk of cervical cancer will be studied.