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Epidemiology and Infection
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Original Paper
*These authors contributed equally to this
study.
Cite this article: Chen L et al (2021). The
genomic distribution map of human
papillomavirus in Western China. Epidemiology
and Infection 149, e135, 1–9. https://doi.org/
10.1017/S0950268821001175
Received: 3 March 2021
Revised: 28 April 2021
Accepted: 11 May 2021
Keywords:
Cervical cancer; China; genotypes; Human
papillomavirus (HPV); prevalence
Author for correspondence:
Xiaosong Li,
E-mail: lixiaosong@cqmu.edu.cn
© The Author(s), 2021. Published by
Cambridge University Press. This is an Open
Access article, distributed under the terms of
the Creative Commons Attribution licence
(http://creativecommons.org/licenses/by/4.0/),
which permits unrestricted re-use,
distribution, and reproduction in any medium,
provided the original work is properly cited.
The genomic distribution map of human
papillomavirus in Western China
Ling Chen1,*, Yan Dong2,*, Jiao Li3,*, Jinqiu Zhao4,*, Dan Wang5,*,LiXu
6,*,
Yue Wu7, Huandong Liu8, Jungao Lu9, Zuoyi Yao10 and Xiaosong Li11
1
The Center of Experimental Teaching Management, Chongqing Medical University, Chongqing 401331, China;
2
Department of Microbiology and Immunology, Kunming Medical University, Kunming 650031, China;
3
Department
of Obstetrics and Gynecology, The First Affiliated Hospital of Xi’an Jiaotong University, Xian, China;
4
Department
of Infectious Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China;
5
Department of Clinical Laboratory, People’s Hospital of Rongchang District, Rongchang, Chongqing 402460,
China;
6
Department of Clinical Laboratory, the First Affiliated Hospital of AMU, Chongqing 400038, China;
7
Oncology Department, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China;
8
Department of Neurosurgery, People’s Hospital of Tibet Autonomous Region, Lhasa 850000, China;
9
Department
of Clinical Laboratory, The Third Affiliated Hospital of Guizhou Medical University, Duyun 558000, China;
10
Department of General Surgery, The Chengdu Fifth People’s Hospital, Chengdu 611130, China and
11
Clinical
Molecular Medicine Testing Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing
400016, China
Abstract
Human papillomavirus (HPV) has been confirmed as the causative agent for cervical cancer.
In this study, a total of 301 880 women were recruited from four different regions of Western
China, with 301 880 exfoliated cervical cell samples collected from women for DNA isolation
and purification. The HPV genotype was tested by polymerase chain reaction. The overall
HPV prevalence rate, high-risk (HR) HPV infection rate, low-risk (LR) HPV infection rate
and mixed HPV infection rate was 18.24%, 79.14%, 12.56% and 8.30%, respectively. The
four most common HR HPV subtypes were HPV-52, 16, 58 and 53, which accounted for
20.49%, 19.93%, 14.54% and 10.01%, respectively. In LR HPV genotype, HPV-6 ranked the
highest (28.17%), followed by HPV-81 (9.09%) and HPV-11 (3.78%). HPV genotype sub-
group analysis also showed that single-type infection was the most common (77.26%)
among HPV-positive individuals. Among multi-infection genotypes, double infection was
the most common with frequencies of 76.04%. The overall prevalence of HPV is high in
Western China, whose distribution demonstrates different patterns across different ages and
regions. Viral genotypes HPV 53, 6 were frequently detected in this population, which is
worth of significant clinical attention.
Introduction
Cervical cancer, a leading genital cancer, is considered as the third most common gynaecologic
malignancy and the fourth most common cause of death from cancer in women, with an esti-
mation of 570 000 new cases and 311 000 new deaths in 2018 (GLOBOCAN, 2018) [1,2].
Compared with developed countries, the age-standardised incidence rate of cervical cancer
is higher in developing countries (16.7 per 100 000 vs. 12.7 per 100 000 women-years, respect-
ively) [3]. China accounts for around 14% of the world’s annual cases of cervical cancer [4,5].
Thus, cervical cancer remains a relatively heavy burden of public hygiene management with
increasing morbidity and mortality rates of cervical cancer in young women in China [6,7].
Human papillomavirus (HPV), a sexually transmitted DNA virus from the Papovaviridae
family, has been confirmed as the causative agent for cervical cancer [8]. It is estimated that
most sexually active adults have been infected by at least one HPV genotype [9]. If the infec-
tion with the high-risk (HR) HPV strains persists, which could be a well-established cause of
cervical cancer [10]. More than 200 distinct HPV genotypes have been discovered to date, of
which approximately 40 infect the mucosal epithelium of the anus and genital tract [11].
Generally, they are classified as HR HPV (carcinogenic HPV types, HR-HPV), low-risk
HPV (non-carcinogenic HPV types, LR-HPV) and intermediate-risk HPV (IR-HPV) based
on their carcinogenic risk or reported potential pathogenicity [12].
It is well known that this type of malignancy is one of the most preventable cancers.
Currently, part of comprehensive strategies aimed at control of cervical cancer is based on vac-
cination against HPV and HPV-based screening programmes, which have been demonstrated
to effectively eliminate the burden of cervical cancer worldwide [13,14]. Nonetheless, the
prevalence and genotype distribution of HPV infections are heterogeneous widespread (differ-
ences vary among nations and regions, as well as within a country), which resulted in progress
towards prevention often frustrating [15]. Hence, an accurate understanding of the regional
distribution characteristics of HPV genotypes is extremely
important for both prophylactic vaccine-based HPV development
and for HPV-based cervical cancer screening strategies.
Reports about large-scale data on the genotypic spectrum of
HPV infection are limited in China. Therefore, we conducted a
retrospective summary of the enormous amount of HPV geno-
types distribution data in China, the overall prevalence, age-
specific prevalence and genotype distribution of HPV in different
regions were also calculated and analysed. This study would
provide guidance for the development of future screening and
prevention programmes.
Materials and methods
Ethical considerations, study population and sample collection
This investigation was approved (No. 2020-173) by the Ethics
Committee of the First Affiliated Hospital of Chongqing
Medical University Ethics Review Board and informed consents
were obtained from all participants for inclusion in the study.
Briefly, this retrospective study collected 301 880 samples from
over eight clinical hospitals, women’s health centres, clinics and
physical examination centres located in four different provinces
of China. For each woman, the HPV genotyping results and rele-
vant clinical information, including age and regional data were all
collected.
DNA extraction and HPV genotyping
Exfoliated cervical cell samples were collected from women by
gynaecologists or obstetricians using a specialised cervical sampler
brush for DNA isolation and purification. Based on rapid flow-
through hybridisation of nucleic acid molecules, a gene chip
detection system for nucleic acids identification of 21 HPV
types was provided by Kaipu Biochemical Company in
Chaozhou, Guangdong, China. Among 21 HPV types, there
were 14 HR-HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56,
58, 59, 66 and 68), six LR-HPV types (6, 11, 42, 43, 44 and 81)
and one IR-HPV type (53).
Subsequently, all HPV tests were performed with an HPV
genotyping panel (polymerase chain reaction (PCR)-reverse dot-
blot hybridisation method). Briefly, according to manufacturer’s
instructions, PCR was performed in a 25-μl reaction mixture con-
taining 1-μl extracted DNA, 0.75-μl DNA Taq polymerase and
23.25-μl PCR-mix solution containing primer system. The PCR
cycling parameters were as follows: an initial step at 95°C for 9
min, and followed by 40 amplification cycles (denaturation at
95°C for 20 s, annealing at 55°C for 30 s, 72°C for 30 s and a
final extension at 72°C for 5 min). After amplification, HPV geno-
typing was performed by hybridisation and RDB on the strips
fixed with HPV type-specific probes. The HPV type-specific
probes immobilised on nylon membranes were used for reverse-
blot hybridisation and detection of all HPV genotypes in a single
assay in accordance with the manufacturer’s instructions.
Simultaneously, in order to validate the HPV test, sterile water
was used as the negative control, and specimens with known
HPV genotypes as the positive control.
Statistical analysis
Data were analysed with IBM SPSS version 21.0. Sample charac-
teristics including age (women with unknown ages were
excluded), region, HPV infection result and genotypes distribu-
tion characters were summarised using frequency distributions
to generate the numbers and percentages. The χ
2
test was adopted
to compare the HPV prevalence or proportions among different
groups. A two-sided P-value of less than 0.05 (P< 0.05) was con-
sidered statistically significant.
Results
Overall HPV infection prevalence and genotype distribution
A total of 301 880 samples were collected and detected by HPV
genotype. The genotype test showed 55 071 samples were HPV
positive, the overall HPV prevalence rate was 18.24%, of which
28.14% in Tibet Autonomous Region, 18.59% in Chongqing
Municipality, 10.33% in Guizhou Province and 29.09% in
Shaanxi Province. Among the four different provinces, autono-
mous regions and municipalities, there were significant differ-
ences in the HPV prevalence (χ
2
= 6120.54, P< 0.001). The
details of genotypes distribution were shown, respectively, in the
following contents.
Age and genotype distribution of HPV infection in different
regions
The HPV prevalence in Tibet Autonomous Region
A total of 36 073 samples were obtained in Tibet Autonomous
Region and the HPV prevalence was identified as 28.14%
(n= 10 150). The highest HPV detection rate was found in the
group aged 36–50 years old (detection rate = 53.40%) (Fig. 1).
Among HPV-positive women, the HR-HPV infection accounted
for 73.51% (n= 7461). In HR-HPV, type 16 (19.44%) and 52
(21.50%) were the most prevalent genotypes, followed by 53
(11.23%) and 58 (11.83%). Among 1428 cases of LR-HPV infec-
tion, the two most common LR-HPV were type 6 (14.13%) and
81 (11.15%). The rates of single and multiple (infection with ⩾2
different HPV genotypes) infections were 70.35% (n= 7141)
and 29.65% (n= 3009), respectively, with double infections rate
at 71.32% among the multiple infections. Among the mixed
(co-infection with HR-HPV and LR-HPV) infection cases, double
HPV genotype infection took up over a half (n= 761). In multiple
infection of HR-HPV, the double HPV genotype infection was
also the highest in 1298 cases. The detailed genotype distribution
Fig. 1. Age distribution of HPV infection in Tibet Autonomous Region.
2 Ling Chen et al.
of HPV infection was described in Figures 2 and 3. Overall, the
prevalence of HPV infection in the Tibet Autonomous Region
was dominated by single HR-HPV infection, especially type 16
or 52.
HPV infection in Chongqing municipality
A total of 37 389 women was detected as HPV positive among the
201 089 samples in Chongqing Municipality, with an HPV infec-
tion rate of 18.59%. Similar to Tibet Autonomous Region, the
highest HPV detection rate was found in the group aged 36–50
years old (detection rate = 52.96%) (Fig. 4). Among the infected
women, HR-HPV infection made up 81.32% (n= 30 406).
Among HR-HPV infection, the three most prevalent types were
type 16, 52 and 58, with frequencies of 20.82%, 20.80% and
15.64%, respectively. The most common LR-HPV types were
HPV 6 (35.65%), even exceeded the most prevalent HR-HPV
genotype (Figs 5 and 6). The rates of single and multiple infec-
tions were 79.00% (n= 29 537) and 21.00% (n= 7852), respect-
ively, with a double infections rate at 77.06% among the
multiple infections.
HPV infection in Guizhou Province
Among 60 205 women of Guizhou Province, the prevalence of
HPV infection was 10.33%, with 6219 cases identified as
HPV positive. In all detected age groups, the highest HPV
detection rate was found in the group aged 20–30 years old
(detection rate = 43.18%) in Guizhou Province (Fig. 7). Among
HPV-positive women, the HR-HPV infection took up 62.58%
(n= 3892). Among HR-HPV infection, the four most prevalent
types were type 52, 16, 58 and 53 in descending order. The
most common LR-HPV types were HPV 6 and 11 (Figs 8 and 9).
The rates of single and multiple infections were 79.71%
(n= 4957) and 20.29% (n= 1262), respectively, with a double
infections rate at 82.96% (n= 1047) among the multiple. The
HR-HPV infection was also the dominant one in Guizhou
Province with 3892 cases (62.58%).
HPV infection in Shaanxi Province
A total of 4513 samples was recorded in Shaanxi Province, with
1313 samples identified as HPV positive (29.09%). In all detected
age groups, the highest HPV detection rate was found in the
Fig. 2. Genotype distribution of HR-HPV infection in Tibet
Autonomous Region.
Fig. 3. Genotype distribution of LR HPV infection in Tibet Autonomous Region. Fig. 4. Age distribution of HPV infection in Chongqing Municipality.
Epidemiology and Infection 3
group aged 26–55 years old (detection rate = 79.06%) in Shaanxi
Province (Fig. 10). Among HPV-positive women, the HR-HPV
infection accounted for 80.05% (n= 1051). The four most preva-
lent HR-HPV types were type 16, 52, 58, 53 in descending order.
The most common LR-HPV types were HPV 6 and 81 (Figs 11
and 12). The rates of single and multiple infections were
69.92% (n= 918) and 30.08% (n= 395), respectively. Among the
multiple infections, double genotypes infections were the domin-
ant one, which made up 69.62% (n= 275).
Fig. 5. Genotype distribution of HR-HPV infection in Chongqing Municipality.
Fig. 6. Genotype distribution of LR HPV infection in Chongqing Municipality.
Fig. 7. Age distribution of HPV infection in Guizhou Province.
Fig. 8. Genotype distribution of HR-HPV infection in Guizhou Province.
Fig. 9. Genotype distribution of LR HPV infection in Guizhou Province.
Fig. 10. Age distribution of HPV infection in Shaanxi Province.
4 Ling Chen et al.
HPV genotype distribution in all positive samples
A total of 55 071 positive samples was detected in this study. We
also analysed the genotype distribution for better decision making
on the HPV vaccine tragedy. Notably, HPV 52 (11282, 20.49%),
16 (10974, 19.93%), 58 (8007, 14.54%), 53 (5513, 10.01%) were
the top four prevalent genotypes among HR-HPV, and HPV 6
(15515, 28.17%), 81 (5008, 9.09%), 11 (2082, 3.78%) were the
top three prevalent genotypes among LR-HPV. Table 1 showed
the detailed genotype distribution.
Age distribution in all positive samples
To better understand the age distribution of HPV infection, after
dividing the subjects into 14 age groups (⩽15, 16–20, 21–25,
26–30, 31–35, 36–40, 41–45, 46–50, 51–55, 56–60, 61–65, 66–
70, 71–75, ⩾76 years), the HPV infection prevalence of different
regions in each age group was analysed (Table 2). It could be dir-
ectly observed that HPV infection happened in all ages, and
women aged 26–50 years accounted for a main part (Fig. 13).
Elder women (>50) and young girls (⩽25) had a relatively lower
HPV infection proportion. Besides, we conducted a χ
2
test to
determine whether the difference of age distribution was signifi-
cant in different regions. The result showed that there was a sig-
nificant difference among these groups (χ
2
= 32.83, P< 0.001). We
summarised the age distribution in three HPV infection patterns,
including HR-HPV only, LR-HPV only, mixed HR-HPV and
LR-HPV HPV infections, which showed that the pattern of
HR-HPV only was the dominate infection one (Table 3).
Age distribution of dominant types
The most common five types of HPV were as follows on the basis
of the above results: the HR-HPV genotype HPV 52, HPV 16,
HPV 58, HPV 53 and LR-HPV 6. As for the five most prevalent
genotypes, we decided to further explore their distribution char-
acteristics in different age groups. Among type 52, 16, 58 and
53, the number of infection cases increased gradually and reached
its highest point in the group aged 41–45 years old, while for
groups aged over 41–45, the number of infection cases was
reduced. Interestingly, in type 6, the most common infection
age was found in women in 21–30 years old (Fig. 14). Women
aged 36–40 years old and 46–50 years old also manifested an
abundant number in these five genotypes HPVs. According to
these results, we could come to the conclusion that women
aged 36–50 years old account for the vast majority of these five
dominant HPV infections.
Discussion
A comprehensive estimation among women worldwide showed
that HPV prevalence in Eastern Asia including China was signifi-
cantly higher than that of both Southeastern Asia and
Fig. 11. Genotype distribution of HR-HPV infection in Shaanxi Province.
Fig. 12. Genotype distribution of LR HPV infection in Shaanxi Province.
Table 1. Genotype distribution of the total population
Genotype Cases Prevalence (%)
HR-HPV 16 10 974 19.93
18 2998 5.44
31 1971 3.58
33 3200 5.81
35 667 1.21
39 3454 6.27
45 630 1.14
51 3013 5.47
52 11 282 20.49
53 5513 10.01
56 1419 2.58
58 8007 14.54
59 1276 2.32
66 1749 3.18
68 2813 5.11
LR-HPV 6 15 515 28.17
11 2082 3.78
42 536 0.97
43 691 1.25
44 571 1.04
81 5008 9.09
Epidemiology and Infection 5
South-central Asia, where HPV prevalence were 13.6%, 6.2%,
7.5%, respectively [5]. In addition, the prevalence of HPV in
less developed countries (15.5%) was higher than that in more
developed countries (10.0%), and Eastern Asia remains the
most heavily burdened HPV region in Asia [5]. The number of
HPV infection cases varies widely among Eastern Asian countries,
as the most populous developing country, China faces a serious
burden [16]. Moreover, it has been shown that Western China
ranks the most in mortality rate and the second-most in cervical
cancer incidence rate nationwide, thus the primary prevention of
cervical cancer of Western China is particularly important [17].
In the present analysis, the overall HPV prevalence of 301 880
western Chinese women with normal cervical cytology was esti-
mated to be at 18.24%, which was higher than the average global
level, lower than that of many other countries, such as Eastern
Africa, and Russia, and higher than that of Japan and India
[5,15]. A large comparable population-based study of HPV geno-
type prevalence nationwide showed a similar overall HPV infec-
tion of 21.07% with 120 772 samples from 37 cities in China
tested [18], which was relatively higher than the overall HPV
prevalence (18.24%) in this study. Regarding the HPV prevalence
in different regional groups, this present survey also showed the
high HPV prevalence: Tibet Autonomous Region (28.14%),
Chongqing Municipality (18.59%), Guizhou Province (10.33%)
and Shaanxi Province (29.09%). Compared with region-based
data, the rates obtained in our study were different from those
previously reported data from neighbouring regions, including
Chongqing (26.20%) [19], Guizhou (16.95%) [20] and Yunnan
(12.90%) [21] of Western China. The reported results of HPV
prevalence vary from study to study as it is possibly caused by sev-
eral variables, including the large Chinese population compos-
ition and territories. Together, the overall HPV-positive rate in
the current study involving 301 880 cases was found to have
increased slightly.
When stratified by HPV genotype, the most common
HR-HPV types detected in our analysis were HPV52 (20.49%),
which was inconsistent with the previous data generated by
some Chinese population-specific investigations and some related
Table 2. Age distribution of HPV infection in Western China
Age Tibet Chongqing Guizhou Shaanxi Total
⩽15 2 21 23 5 51 (0.09%)
16–20 125 560 696 10 1391 (2.53%)
21–25 560 2579 1466 64 4669 (8.48%)
26–30 1139 4154 1157 147 6597 (11.98%)
31–35 1172 4698 640 171 6681 (12.13%)
36–40 1473 6568 565 174 8780 (15.94%)
41–45 2390 7657 657 220 10 924 (19.84%)
46–50 1557 5578 458 180 7773 (14.11%)
51–55 847 2706 260 146 3959 (7.19%)
56–60 334 1433 169 105 2041 (3.71%)
61–65 308 892 71 49 1320 (2.40%)
66–70 133 345 33 31 542 (0.98%)
71–75 73 145 13 8 239 (0.43%)
⩾76 37 53 11 3 104 (0.19%)
Total 10 150 37 389 6219 1313 55 071 (100%)
Fig. 13. Age distribution rate in total population.
6 Ling Chen et al.
studies reported that HPV 16 was identified as the most common
HR HPV genotype [5,18,22–24]. The other three most prevalent
HR/IR-HPV types were HPV16, 58 and 53, with frequencies of
19.93%, 14.52%, 10.01%, respectively. The characteristics of
HPV distribution in our study were similar to a recent HPV
study in Guizhou, China [20]. However, a recent study enrolling
37 722 females showed that the four most prevalent genotypes
were HPV 16 (3.79%), HPV 52 (2.47%), HPV 58 (1.76%) and
HPV 53 (1.35%) [17], which was different from our data. In add-
ition, compared with a nationwide data of Chinese population-
based research from 37 cities, except for HPV53 (not reported),
the infection rates of HPV16 (4.82%), HPV52 (4.52%) and
HPV58 (2.74%) were all lower than those in our study [18].
The knowledge of HPV prevalence and subtype distribution in
different regions might facilitate the development of vaccination
programme implementation. In this study, the HPV infection
types and their proportions varied in different regions: the top
three HPV genotypes were HPV 52, 16, 58 in Tibet
Autonomous Region, HPV 16, 52, 58 in both Chongqing
Municipality and Shaanxi Province and HPV 52, 16, 58 in
Guizhou Province. Therefore, different regions showed diversity
and had their respective proportions with respect to HPV geno-
types. The differences in economic conditions, geographical cul-
tural habits, migrations and other multiple factors might affect
lifestyles among different populations, thus explaining the differ-
ence in the observed HPV prevalence.
Interestingly, among HR-HPV genotype infections, HPV53
type infection accounted for the top four in our study (10.01%).
HPV53, a traditionally non-vaccine genotype, was recognised as
a probable HR genotype and recently demonstrated to be asso-
ciated with the putative potency of viral carcinogenicity (odds
ratio, 3.92) [23,25]. Moreover, the prevalence of the HPV53
genotype gradually elevated from 2011 to 2015 [23]. It was also
reported as the fifth most common HPV type detected in
Eastern Africa and Central and Northern America [5]. Thus,
HPV prophylactic vaccines, including HPV53, may offer more
sufficient protection for women in China.
In the present study, we found that the three most common
LR-HPV types were HPV6 (28.17%), HPV81 (9.09%) and
HPV11 (3.78%). A recent analysis involving 94 489 women
from Eastern China conducted in 2019 has shown that the dom-
inant LR-HPV genotypes were HPV81 and HPV6 [26].
Furthermore, a previous cross-sectional survey conducted in
Arab women reported that HPV 81, 11 and 6 were the most com-
monly identified LR HPV genotypes in decreasing order [27],
which were inconsistent with our research. The high HPV 6
prevalence in our study was unexpected. The reasons for this
deviation of LR-HPV distribution are unclear and may be due
to the cultural differences of the nationalities. Therefore, the
HPV vaccine in China might also consider including the HPV
6 genotype.
When it comes to the HPV infection proportion of different
age subgroups, the age distribution in this study showed that
the middle age group (26–50 years) presented the highest HPV
detection rate (75.53%, 71.82%, 62.75%, respectively) among HR
HPV only, LR HPV only and mixed HPV genotype subgroups,
with all subgroups indicating relatively lowest detection rate in
elderly individuals (⩾76 years), similar to few recent studies in
China [20,28]. The most frequent age group of our HPV screen-
ing population was 25–50 years, which could explain the reason
why the HPV types were distributed in this manner.
Interestingly, we also concluded that the age distribution varied
across different HPV genotypes in our study. As for the top
four HR-HPV (type 52, 16, 58 and 53), the highest HPV detection
rate was found in the group aged 41–45 years old, while the high-
est HPV detection rate in LR-HPV 6 infection in the group aged
21–30 years old group, which was different from a previous study
concerning HPV genotyping results in China [22]. However, our
results were consistent with the clinical phenomenon that increas-
ingly frequent diagnoses of cervical cancer occurred in middle/
old-aged Chinese women (40–64 years old). Therefore, it has
become particularly important to disseminate information about
cervical diseases as well as carry out HPV infection screening in
China in line with the HPV distribution characteristics of each
age group.
Among the patients infected with multiple subtypes,
co-infections with two HPV types were the most common
(76.04%) in our study, which was comparable to the regional
results of Guangzhou, Sichuan and Macao in China from the pre-
vious reports [29–31]. Many epidemiologic studies found that
infection with multiple HPV genotypes seemed to increase the
risk of developing the tissue abnormalities or high-grade lesions
that precede invasive cervical cancer considerably, because HPV
types might interact synergistically, which might contribute to
increasing the baseline risk observed with single-type infections
[27,32]. Similar results have been produced by other studies
that confirmed its association with the development of the cer-
vical carcinogenesis and increased the duration of the viral infec-
tion [33]. Therefore, it was suggested to consider diagnoses of
co-infection with HPV into the prediction outcomes of HPV
infections.
This is the first HPV distribution study with a large sample
size in China. The principal strength of this study was that the
large data enrolling 0.3 million women come from Western
China, thus making it a representative of the general women
population in China. One limitation of this study was sampling
bias, because the most frequent age group of our HPV screening
Table 3. Age distribution in different HPV infection patterns
Type
Age HR only LR only Mixed
⩽15 32 13 6
16–20 852 313 226
21–25 3266 823 580
26–30 5047 993 557
31–35 5418 839 424
36–40 7187 968 625
41–45 8955 1275 694
46–50 6313 893 567
51–55 3137 450 372
56–60 1633 177 231
61–65 1043 107 170
66–70 428 46 68
71–75 196 12 31
⩾76 78 8 18
Total 43 585 6917 4569
Epidemiology and Infection 7
strategy was 25–50 years. Secondly, the women enrolled in this
study attended to clinics for seeking medical advice based on rou-
tine gynaecological examination and HPV prevalence results, they
always were accompanied by some clinical symptoms, which may
lead to an over-reporting of HPV prevalence in this research.
In addition, no clinical characters and cervical cytology results
were collected as part of the study, resulting in the specific risk
factors for the cervical cancer and the correlation between HPV
genotype and cervical cancer or precancerous lesions were unable
to be accurately examined. Furthermore, a follow-up study should
be conducted to track changes in genotype, cervical pathology and
cytology as there was a close relationship between cervical carcin-
oma and long-term persistent HR-HPV infections.
Thus, our results indicate that the preventative strategies
including HPV vaccine-based popularisation and related educa-
tional campaigns should start in 25-year-old females. This infor-
mation might provide valuable information for estimation of the
potential clinical benefit of HPV-based screening in China.
Conclusions
This study represents one of the most comprehensive studies of
the prevalence and genotype distribution of different HPV types
in China to date. We examined the epidemiology of HPV infec-
tion in China and confirmed the high overall HPV prevalence
rate (18.24%) in all female subjects. Moreover, in addition to com-
mon genotype HPV52, 16 and 58, particular attention should be
paid to the high prevalence of non-vaccine genotypes
(e.g. HPV53, HPV6) in China. Therefore, the future next-
generation HPV prophylactic vaccines in China should also con-
sider to include more HPV types (e.g. HPV53, HPV6). Regarding
the age-specific distribution of HPV, the highest HPV detection
rate was found in age group 26–50 years old (detection rate =
74.00%). These results showed that the majority of HPV infec-
tions in China might be occurring in middle-aged women,
which reminds us to attach great importance to middle-aged
women in the prevention and control of HPV.
Data. The raw data are available on request by the editor of the publishing
journal.
Acknowledgements. This study was sponsored by the Clinical Molecular
Medicine Testing Center, The First Affiliated Hospital of Chongqing
Medical University. We would like to acknowledge all members of the
Clinical Molecular Medicine Testing Center. We appreciate all the patients
and their parents for participating in the study.
Author contributions.
YD, JL, DW, LX and JLu carried out the sample collection, laboratory detection and
drafted the manuscript. LC and XL participated in the design of the study and performed
the statistical analysis. YW, HL, ZY and XL conceived of the study, and participated in its
design and coordination and helped to draft the manuscript. All authors read and
approved the final manuscript.
Financial support. This study was funded by the Chongqing Yuzhong
District Technology Project (grant no. 20160136).
Conflict of interest. None.
Ethical standards. This study was approved by the Ethics Committee of the
First Affiliated Hospital of Chongqing Medical University Ethics Review Board
(no. 2020-173).
Data availability statement. All data generated or analysed during this
study are included in this published article.
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