Human papillomavirus (HPV) infection is the main cause of cervical cancer and major viruses related to carcinogenesis in various malignant diseases such as cervical cancer, vaginal cancer, vulvar cancer, anal cancer, and head and neck cancer. Cervical cancer is the second most prevalent female cancer in the world and the fourth in Korea. Prophylactic HPV vaccines in widespread use include the used in South Korea to prevent cervical cancer are bivalent (2-valent HPV vaccine; Cervarix), quadrivalent (4-valent HPV vaccine; Gardasil), and nonavalent (9-valent HPV vaccine; Gardasil9). Since HPV vaccines the first approval in 2006, 115 countries have include HPV vaccines in their national immunization programs, that its preventive effect is as much as 70%, and that the incidence of high-risk types of HPV has gradually decreased. According to HPV cohort studies in Korea, about 26% of adult women have an HPV vaccination history and show a low incidence of HPV-16/18 genotypes compared to unvaccinated women. In the countries that National Immunization Programs for HPV vaccine were conducted earlier than in Korea, the safety, efficacy, and effectiveness of HPV vaccines have been reported. Therefore, it is considered that basic research including an analysis of the effectiveness of HPV vaccines for policy decisions related to the expanding the HPV vaccine coverage and introducing of new vaccine in the future.

Human papillomavirus is known to be a major cause of cervical cancer. More than 190 HPV genotypes have been identified and classified into a high-risk group (18 genotypes) and a low-risk group (12 genotypes) depending on the risk of disease progression. This report investigated the results of domestic and overseas studies on HPV prevalence and genotype distribution; identified prevalence and genotype distribution in Korea and in the world; and described and presented the results obtained as part of an internal research project at the KNIH. Through systematic review and meta-analysis, the previous study shows that the prevalence of HPV was found to be 10.7% (worldwide) and 13.6% (Korea and China) in women with normal cytology, respectively. HPV-16, HPV-18, HPV-31, HPV-58, and HPV-52 were the five most prevalent genotypes in the world. By contrast, in East Asia, including Korea, HPV-16, HPV-18, HPV-58, HPV-52, and HPV-70 were the prevalent genotypes. In an intramural research project conducted by the KNIH, the prevalence of HPV was estimated to be about 36% according to a meta-analysis. This result provides the basic statistics of HPV infection in Korea.

Objective: To evaluate human papillomavirus (HPV) vaccine effectiveness in a cohort of Korean women infected with HPV. Methods: From 2010 to 2021, Korean women aged 20–60 years who diagnosed HPV-positive atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion were recruited from 6 hospitals. HPV vaccine effectiveness was estimated by observing the differences in pathological and clinical information and experimental results— prevalence, viral load (VL), physical state (PS), and HPV16/18 infection duration—between the vaccinated and unvaccinated groups. Results: HPV16/18 prevalence declined from 18.5% to 11.8% as vaccination rates increased from 14.3% to 60.7% in the 1,757 registered cohort women. DNA analysis from 96 samples collected from the participants, indicated that HPV vaccination reduced HPV16 VL by 6 times and increased E2/E6 ratio for both HPV16 and HPV18 by 1.4 and 5 times, respectively. The HPV16 infection rate—lasting more than 18 months from 31.0% to 21.6%—and the HPV18 infection rate—lasting more than 12 and less than 24 months from 35.5% to 21.1%—were reduced by vaccination. We found VL and the infection duration to be directly proportional.Moreover, HPV vaccination reduced not only the VL to 1/4 in both the persistence and clearance groups but also the persistence rate from 90% (27/30) to 70.6% (12/17) in HPV16. Conclusion HPV vaccination reduced the prevalence and duration of infection and kept the PS in an episomal form for both HPV16 and HPV18. The tendency of persistence VL to be higher than clearance in the unvaccinated group implies that the vaccine’s effect of reducing VL in HPV16 may lower the risk of progression to cervical cancer by shortening the infection duration.

Objective: To evaluate human papillomavirus (HPV) vaccine effectiveness in a cohort of Korean women infected with HPV. Methods: From 2010 to 2021, Korean women aged 20–60 years who diagnosed HPV-positive atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion were recruited from 6 hospitals. HPV vaccine effectiveness was estimated by observing the differences in pathological and clinical information and experimental results— prevalence, viral load (VL), physical state (PS), and HPV16/18 infection duration—between the vaccinated and unvaccinated groups. Results: HPV16/18 prevalence declined from 18.5% to 11.8% as vaccination rates increased from 14.3% to 60.7% in the 1,757 registered cohort women. DNA analysis from 96 samples collected from the participants, indicated that HPV vaccination reduced HPV16 VL by 6 times and increased E2/E6 ratio for both HPV16 and HPV18 by 1.4 and 5 times, respectively. The HPV16 infection rate—lasting more than 18 months from 31.0% to 21.6%—and the HPV18 infection rate—lasting more than 12 and less than 24 months from 35.5% to 21.1%—were reduced by vaccination. We found VL and the infection duration to be directly proportional.Moreover, HPV vaccination reduced not only the VL to 1/4 in both the persistence and clearance groups but also the persistence rate from 90% (27/30) to 70.6% (12/17) in HPV16. Conclusion HPV vaccination reduced the prevalence and duration of infection and kept the PS in an episomal form for both HPV16 and HPV18. The tendency of persistence VL to be higher than clearance in the unvaccinated group implies that the vaccine’s effect of reducing VL in HPV16 may lower the risk of progression to cervical cancer by shortening the infection duration.

Objective: To evaluate human papillomavirus (HPV) vaccine effectiveness in a cohort of Korean women infected with HPV. Methods: From 2010 to 2021, Korean women aged 20–60 years who diagnosed HPV-positive atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion were recruited from 6 hospitals. HPV vaccine effectiveness was estimated by observing the differences in pathological and clinical information and experimental results— prevalence, viral load (VL), physical state (PS), and HPV16/18 infection duration—between the vaccinated and unvaccinated groups. Results: HPV16/18 prevalence declined from 18.5% to 11.8% as vaccination rates increased from 14.3% to 60.7% in the 1,757 registered cohort women. DNA analysis from 96 samples collected from the participants, indicated that HPV vaccination reduced HPV16 VL by 6 times and increased E2/E6 ratio for both HPV16 and HPV18 by 1.4 and 5 times, respectively. The HPV16 infection rate—lasting more than 18 months from 31.0% to 21.6%—and the HPV18 infection rate—lasting more than 12 and less than 24 months from 35.5% to 21.1%—were reduced by vaccination. We found VL and the infection duration to be directly proportional.Moreover, HPV vaccination reduced not only the VL to 1/4 in both the persistence and clearance groups but also the persistence rate from 90% (27/30) to 70.6% (12/17) in HPV16. Conclusion HPV vaccination reduced the prevalence and duration of infection and kept the PS in an episomal form for both HPV16 and HPV18. The tendency of persistence VL to be higher than clearance in the unvaccinated group implies that the vaccine’s effect of reducing VL in HPV16 may lower the risk of progression to cervical cancer by shortening the infection duration.

Adult ; Atypical Squamous Cells of the Cervix ; Education ; Female ; Genotype ; Humans ; Immunization Programs ; Korea ; Papanicolaou Test ; Prevalence ; Retrospective Studies ; Single Person ; Squamous Intraepithelial Lesions of the Cervix ; Uterine Cervical Neoplasms ; Vaccination ; Vaccines

Objectives: Since 2007, human papillomavirus (HPV) vaccines have been administered for the prevention of cervical cancer in Korea. We investigated the status of HPV vaccination among HPV-infected adult women with abnormal cervical cytology before the introduction of National Immunization Program. Methods: From 2010 to 2016, HPV-positive women (age, 20–60 years) with atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion (LSIL) were enrolled from five hospitals across Korea. Their HPV genotype, epidemiologic, and clinical data, including HPV vaccination history, were obtained. We compared the epidemiological characteristics and prevalence of HPV-16/18 genotypes between vaccinated and unvaccinated women. Results: Among the 1,300 women, approximately 26% had a history of vaccination. Vaccinated patients were significantly younger, unmarried, and had a higher education level than unvaccinated women. For HPV-vaccinated individuals by vaccine dose, there was a significant younger age at vaccination initiation (p=0.025), longer duration from HPV vaccination to Pap test date (p=0.001), and lower proportion of HPV-16/18 (p=0.028) in the women with three doses. There was a significantly lower prevalence of HPV-16/18 genotypes in women who were vaccinated at least 12 months prior than in unvaccinated women(adjusted prevalence ratio [aPR]=0.51; 95% confidence interval [CI]=0.29–0.88). For women with LSIL, the prevalence of the HPV-16/18 genotypes was significantly lower in women who were vaccinated more than 12 months prior than in unvaccinated women (aPR=0.35; 95% CI=0.13–0.96). Conclusion This study highlighted the status of HPV vaccination and the prevalence of HPV-16/18 genotypes among HPV-infected women with abnormal cervical cytology according to HPV vaccination. It provides preliminary information regarding the status of HPV vaccination among Korean adult women.