Gross HPV prevalence
Data from 49,955 HPV screening tests performed between 2018 and 2020 were included. The age of all the patients ranged from 14 to 91 years, with an average of 41.9 ± 11.1 years. A total of 7286 patients, accounting for 14.59% of the total population, were HPV positive. Among them, 5507 (75.58%) were infected with high-risk genotypes, and 1779 (24.42%) were infected with only low-risk subtypes.
HPV prevalence by age group
All patients were categorized into seven age groups (<20, 20–29, 30–39, 40–49, 50–59, 60–69, and ≥ 70 years). The HPV prevalence curve specific to the seven age groups showed a bimodal distribution (Fig. 1). The HPV infection rate of the <20 years group was 27.32% and had the highest peak. In the 20-29, 30-39 and 40-49 years age groups, the infection rates decreased were 13.14%, 13.04% and 13.26%, respectively. With increasing age, the prevalence rate increased to 17.25% in the 50-59 years group, with a second peaked (22.93%) in the 60-69 years group. The ≥ 70 years group accounted for 19.73% of the infected population. Regardless of age group, the positive patients were mainly infected with high-risk HPV genotypes (Table 1). A total of 22.6% of the positive patients in the <20 years group had only low-risk HPV genotypes. The rates in the 20-29, 30-39, 40-49, 50-59, 60-69 and ≥ 70 years groups were 15.71%, 14.99%, 16.09%, 13.23%, 9.30% and 9.71%, respectively.
Of all the HPV genotypes, HPV52 was the most prevalent subtype found in 1674 patients, accounting for 22.98% of infections. However, in the groups aged <20 and 60-69 years, HPV16 ranked first (Table 2, Fig. 2a). Among the low-risk genotypes, HPV81 had the highest infection rate in the 40-49, 50-59, 60-69 and ≥70 years age groups. In addition, HPV06 in the groups aged <20 and 20-29 years and HPV44 in the group aged 30-39 years had the highest infection rates among the low-risk subtypes (Fig. 2b).
Distributions of single and multiple HPV infections in different genotype and age groups
Regarding HPV26, 45, 56, 59, 82, 06, 40, 42 43 and 83, combinations with other subtypes were more common than single infections (Fig. 3). However, single HPV infection was the most prevalent pattern in the different age groups and occurred in 5686 (78.04%) patients (Table 3). The most common multiple-infection situations were dual infections (16.50%), followed by 3-strain infections (3.94%), 4-strain infections (1.04%), 5-strain infections (0.26%), and six-strain or more infections (0.25%) (Fig. 4a). The top 10 dual HPV combinations were as follows: 16/52, 16/58, 52/58, 52/53, 51/52, 18/52, 16/53, 52/81, 51/58 and 52/68 (Fig. 4b). HPV81 was the only low-risk subtype among these 10 combinations. The multiple HPV infection rates in different age groups were different. The highest rate was in the <20 years group and reached 43.78%. As age increased, the rate decreased to 24.89%, 19.02% and 18.53% in the 20-29, 30-39 and 40-49 years groups, respectively. However, the elderly groups (50-59, 60-69 and ≥70 years) accounted for 23.39%, 30.77% and 28.16% of multiple HPV infections, respectively. The distribution also showed a bimodal pattern.
Distribution of HPV subtypes according to different cytological results
To further analyse the 7286 HPV-positive samples, cytological results from 3148 patients in our database were analysed. The distribution of liquid-based cytological examination results of different HPV genotypes is shown in Table 4 and Fig. 5. Among such patients, 1149 (36.50%) had abnormal cytological results. Fig. 5 demonstrates that 3145 HPV-positive women received cytological testing. Among them, 1996 (63.47%) had negative results, and 1149 (36.53%) had cytologic abnormalities. HPV52 was the most common subtype, accounting for 25.26% of NILM, 26.13% of ASC-US and 23.32% of LSIL. However, HPV16 was the leading genotype found in 44.36% of ASC-H, 46.86% of HSIL and 71.43% of SCC, followed by HPV58. Among patients without high-risk HPV infection, HPV81 was the main subtype, accounting for 15 (3.54%) cases of ASC-US, accompanied by HPV61, accounting for 4 (1.58%) cases of LSIL.
Distribution of HPV subtypes according to different pathological results
A total of 2833 participants were referred for histological examination. Among them, 2000 patients had pathological abnormalities (70.60%). The distribution of pathological results of cases due to different HPV genotypes is shown in Table 5 and Fig. 6. Of the 760 cases of LSIL, HPV52 was the dominant subtype (28.68%), followed by HPV16 (15.00%), HPV58 (14.47%) and HPV53 (9.74%). Of the cases of HSIL, HPV16 was the dominant subtype (39.08%), followed by HPV58 (25.77%), HPV52 (21.71%) and HPV33 (10.08%). Of the 481 cases of SCC, HPV16 was the dominant genotype (67.98), followed by HPV58 (11.02%), HPV52 (8.32%) and HPV18 (7.28%). Of the 44 cases of AC, HPV18 (50.00%) and HPV16 (43.18%) were the main genotypes. As shown in Table 6, patients infected with HPV16, 31, 33 and 58 had increased risks of HSIL (OR=1.70, p<0.001; OR=1.99, p=0.01; OR=2.59, p<0.001; OR=2.29, p<0.001). Patients with HPV16 and 18 were at higher risk of cervical carcinoma (including SCC, AC and ASC) (OR=6.72, p<0.001; P=1.67, p=0.001).