Current Status of Human Papillomavirus Infection and Introduction of Vaccination to the National Immunization Program in Korea: an Overview

Efficacy and immunogenicity of AS04-HPV-16/18 vaccine in females with existing cervical HR-HPV infection at first vaccination: A pooled analysis of four large clinical trials worldwide

Females with existing high-risk HPV (HR-HPV) infections remain at risk of subsequent multiple or recurrent infections, on which benefit from HPV vaccines was under-reported. We pooled individual-level data from four large-scale, RCTs of AS04-HPV-16/18 vaccine to evaluate efficacy and immunogenicity in females DNA-positive to any HR-HPV types at first vaccination. Females receiving the AS04-HPV-16/18 vaccine in the original RCTs constituted the vaccine group in the present study, while those unvaccinated served as the control group. Vaccine efficacy (VE) against new infections and associated cervical intraepithelial neoplasia (CIN) 2+ in females DNA-negative to the considered HR-HPV type but positive to any other HR-HPV types, VE against reinfections in females DNA-positive to the considered HR-HPV type but cleared naturally during later follow-up, and levels of anti-HPV-16/18 IgG were assessed. Our final analyses included 5137 females (vaccine group = 2532, control group = 2605). The median follow-up time was 47.88 months (IQR: 45.72-50.04). For the prevention of precancerous lesions related to the non-infected HR-HPV types at baseline, VE against HPV-16/18 related CIN 2+ was 82.70% (95% CI: 63.70-93.00%). For the prevention of reinfections related to the infected HR-HPV types following natural clearance, VE against HPV-16/18 12MPI was non-significant (p > .05), albeit robust immunity persisted for at least 48 months. Females with existing HR-HPV infections at first vaccination still benefit from vaccination in preventing precancers related to the non-infected types at baseline. VE against reinfections related to the infected types following natural clearance remains to be further investigated.

Post-marketing surveillance study of the safety of the HPV-16/18 vaccine in Korea (2017-2021)

Human papillomavirus (HPV) infection is associated with the risk of developing certain cancers, including cancers of the cervix, vulva, vagina, penis, anus, rectum, and oropharynx. In 2016, the bivalent HPV-16/18 vaccine was included in the Korea National Immunization Program. This vaccine protects against HPV types 16 and 18 and other oncogenic HPV types predominant in cervical and anal cancers. This post-marketing surveillance (PMS) study assessed the safety of the HPV-16/18 vaccine in Korea. The study was conducted in males and females aged between 9 and 25 years, from 2017 to 2021. Safety was measured in terms of frequency and intensity of adverse events (AEs), adverse drug reactions (ADRs), and serious adverse events (SAEs) after each vaccine dose. The safety analysis included all participants who were vaccinated as per prescribing information and who completed a 30-day follow-up after at least one dose. Data were collected using individual case report forms. The total safety cohort included 662 participants. A total of 220 AEs were reported in 144 subjects (21.75%), and there were 158 ADRs in 111 subjects (16.77%), with the most common being injection site pain in all cases. No SAEs or serious ADRs were reported. Most AEs were reported after the first dose and were injection site reactions with mild intensity that recovered. No individuals required hospitalization or an emergency department visit. Safety results showed that the HPV-16/18 vaccine was generally well tolerated in the Korean population, and no safety concerns were identified.ClinicalTrials.gov Identifier: NCT03671369.

Prevention Strategies and Early Diagnosis of Cervical Cancer: Current State and Prospects

Cervical cancer ranks third among all new cancer cases and causes of cancer deaths in females. The paper provides an overview of cervical cancer prevention strategies employed in different regions, with incidence and mortality rates ranging from high to low. It assesses the effectiveness of approaches proposed by national healthcare systems by analysing data published in the National Library of Medicine (Pubmed) since 2018 featuring the following keywords: "cervical cancer prevention", "cervical cancer screening", "barriers to cervical cancer prevention", "premalignant cervical lesions" and "current strategies". WHO's 90-70-90 global strategy for cervical cancer prevention and early screening has proven effective in different countries in both mathematical models and clinical practice. The data analysis carried out within this study identified promising approaches to cervical cancer screening and prevention, which can further enhance the effectiveness of the existing WHO strategy and national healthcare systems. One such approach is the application of AI technologies for detecting precancerous cervical lesions and choosing treatment strategies. As such studies show, the use of AI can not only increase detection accuracy but also ease the burden on primary care.

Analysis of HR-HPV Infection Concordance Rates in Cervical and Urine Specimens; Proposal of Additional Cervical Screening Process for Women Who Refuse Invasive Cervical Sampling

This study aimed to provide basic data for the clinical application of urine samples to prevent cervical cancer due to persistent HR-HPV infection in women who refuse invasive cervical sampling. Pairs of cervical swabs and urine samples were collected from 210 asymptomatic women who visited the obstetrics and gynecology department from August to December 2020, and a total of 420 samples were collected. Using the PANA RealTyper™ HPV Screening Kit as a real-time PCR method, paired cervical swabs and random urine samples were tested. A total of 19 samples (9.1%) were both HPV positive and 177 (84.3%) were both negative. The concordance between the two types of samples was 93.3%, with κ = 0.69 (moderate, 95% CI 0.54-0.84). The HPV infection rate by age was highest in both cervical swabs and urine samples in women in their 30s, followed by those in their 20s. Thus, the HPV infection rate was high in young women under 40 at 69.2% in cervical swabs and 61.8% in urine samples. Urine samples are considered a valuable screening test for women who refuse invasive Pap tests to prevent cervical cancer caused by persistent HPV infection.

Perception of human papilloma virus (HPV) vaccination during the COVID-19 pandemic

The COVID 19 pandemic is far from over, and vaccines remain important tool for fighting the disease. As the preventive effects of the COVID-19 vaccine emerges, it is likely that the perception of importance and safety of vaccines have a positive effect on the acceptance of other vaccines. However, it is still unclear how COVID-19 pandemic has affected the general vaccination perception and acceptance. Therefore, the objective of this study was to investigate the impact of the COVID-19 pandemic on the perception of HPV vaccination. This study involved an offline survey of 161 women aged between 20 and 49 years who visited the gynecologic clinic at Chung-nam National University Sejong Hospital from January 2021 to June 2021. The questionnaire consists of items related to experience and knowledge of COVID-19 and HPV viruses, as well as attitudes toward HPV vaccination. Knowledge about COVID-19 virus and HPV correlated positively with their experiences (P = .011 and P = .045, respectively). Positive attitude was increased, and negative attitude was reduced toward HPV vaccination in the COVID-19 pandemic era. Participants stated that accurate information and cost reduction about HPV vaccine was needed to increase the HPV vaccination rate. During the COVID-19 pandemic era, positive attitudes towards HPV vaccination have tended to increase. To increase the HPV vaccination rate, public efforts are needed for further information and cost reduction.

Hypoalbuminemia for the prediction of survival in patients with stage IVB cervical cancer

We evaluated the prognostic significance of malnutrition in patients with metastatic cervical cancer. In this study, we retrospectively analyzed the cases of 43 patients with stage IVB (FIGO2018) cervical cancer treated at our institute from December 2004 to December 2017. We determined the correlation between clinicopathological characteristics and survival by performing univariate and multivariate analyses. The serum albumin value at diagnosis was used as an index of malnutrition. The median follow-up period was 16.4 months (range, 0.9–91.4 months). On Kaplan-Meier analysis, the 1- and 2-year overall survival (OS) rates for all patients were 61.6% and 48.6%, respectively. The optimal serum albumin for predicting 1-year survival was 3.3 g/dL, as determined by the receiver operating characteristic curve to maximize the area under the curve. The OS of the patients with albumin >3.3 g/dL (n = 28) was significantly better than that of the patients with albumin ≤3.3 g/dL (n = 15) (p = 0.004). The univariate and multivariate analyses revealed that pretreatment serum albumin and mode of primary treatment were significantly associated with survival in patients with stage IVB cervical cancer. Hypoalbuminemia was an unfavorable prognostic factor for patients with metastatic cervical cancer.

Analysis of Healthcare Utilization for Primary Dysmenorrhea in Korea: A Retrospective, Cross-Sectional Study

Purpose

This study is a retrospective, cross-sectional study aiming to present basic data on the treatment modalities and cost of care for primary dysmenorrhea (PD) by analyzing healthcare utilization and patient distributions using the 2010 to 2018 Health Insurance Review and Assessment Service (HIRA) data.

Patients and Methods

We used the HIRA-National Patient Sample (NPS) data to analyze medical service utilization for PD (ICD-10 code: N94.4, N94.6) in Western medicine (WM) or Korean medicine (KM) care between January 2010 and December 2018.

Results

There were 41,139 patients diagnosed with PD who utilized Western medicine (WM) or Korean medicine (KM) care at least once during the study period. The number of claims and patients steadily rose over the years from 7430 claims for 3989 patients in 2010 to 11,523 claims for 6226 patients in 2018. The predominant age group was 15 to 24 years. Regarding the frequency of service categories for PD in the claims, consultation was the most common and costly service category in WM (72,120 cases, 47.89%; 631,912 USD, 69.74%), while injection and analogous treatments was the most common and costly service category in KM (97,157 cases, 72.41%; 314,696 USD, 55.86%). Regarding the drug prescriptions, nonsteroidal anti-inflammatory drugs (NSAIDs) (26,617 cases, 40.47%) were the most frequently prescribed drug for PD in pharmacies and hospitals.

Conclusion

The result shows an annual increase in healthcare utilization for PD with the fastest rate in individuals aged 15 to 24 years. This study provides data on the current utilization of WM and KM care for PD for policymakers. Furthermore, we analyzed the frequency and cost of common treatment modalities in WM and KM, which would be useful data for clinicians and researchers.

Cancer Incidence Among Adults With HIV in a Population-Based Cohort in Korea

IMPORTANCE

In combination with a decreased risk of AIDS-defining cancers and improved survival of people infected with HIV, the burden of non-AIDS-defining cancer has increased markedly. Although a substantial number of studies have measured the cancer risk among people with HIV in developed countries, little research has been conducted on the risk of cancer in HIV-infected people in Asia.

OBJECTIVE

To examine the cancer incidence and the estimated risk of cancer among people in Korea infected with HIV compared with the general population.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study evaluated patients without cancer newly diagnosed with HIV from January 1, 2006, to December 31, 2018, using a nationwide population-based claims database embedded in the National Health Insurance Service database. Data were analyzed between December 6, 2021, and February 28, 2022.

EXPOSURES

Infection with HIV.

MAIN OUTCOMES AND MEASURES

Cancer incidence and standardized incidence rate (SIR) through indirect standardization.

RESULTS

A total of 11 552 individuals without cancer (10 444 male [90.4%]; mean [SD] age, 39.9 [11.2] years) diagnosed with HIV were identified. The SIR for all cancers was 1.68 (95% CI, 1.50-1.87) in men and 1.26 (95% CI, 0.89-1.64) in women. In men, the highest SIRs were for Kaposi sarcoma (SIR, 349.10; 95% CI, 196.10-502.20) and anal cancer (SIR, 104.20; 95% CI, 55.56-149.90). The incidence of non-Hodgkin lymphoma (SIR, 15.62; 95% CI, 11.85-19.39), Hodgkin lymphoma (SIR, 16.67; 95% CI, 4.32-29.02), and oropharyngeal cancer (SIR, 2.97; 95% CI, 1.36-4.58) in men infected with HIV was higher than in the general population. In women infected with HIV, an increased incidence of cervical cancer (SIR, 4.98; 95% CI, 1.29-8.66) and non-Hodgkin lymphoma (SIR, 11.78; 95% CI, 2.35-21.21) compared with the general population was observed. The SIR of thyroid cancer in patients with HIV was lower than in the general population in both men (SIR, 0.63; 95% CI, 0.27-0.99) and women (SIR, 0.48; 95% CI, 0.06-0.90).

CONCLUSIONS AND RELEVANCE

In this cohort study, cancer risks, especially AIDS-defining cancer and virus-related cancer, were elevated in people with HIV. Efforts for cancer prevention, screening, and better accessibility to medical care in HIV-infected people are warranted.

Age-specific prevalence and genotype distribution of human papillomavirus in women from Northwest China

BACKGROUND

Human papillomavirus (HPV) is the leading cause of cervical cancer with more than 200 genotypes. Different genotypes have different potentials in causing premalignant lesions and cervical cancers. In this study, we investigated the age-specific prevalence and genotype distribution of HPV genotypes in Northwest China.

MATERIALS AND METHODS

We recruited 145,918 unvaccinated women from Northwest China for population-based HPV DNA screening test during June 2015 to December 2020. And a lab-based test was performed for each volunteer by flow fluorescent technology to identify the genotypes of HPV.

RESULTS

The overall infection rate of HPV was 22.97%. With the participants divided into 12 groups according to age, a bimodal curve of infection rate was obtained. And the two peaks appeared in the younger than 20 group and 61-65 group, respectively. The five most common HPV genotypes included HPV 16, 58, 52, 53 and 61 in all participants, which were in descending order of frequency. Among women younger than 25 years old, HPV 6 and 11 were more common and even higher than some genotypes mentioned above. Among women older than 65 years old, HPV 18 and 66 were more common than or as high as the six most common genotypes in all populations. Additionally, the distribution of single and multiple infections in each age group was also different.

CONCLUSION

The baseline prevalence and genotype distribution of HPV in Northwest China was uncovered for the first time. Age was related to the epidemiology of different HPV genotypes. All the results would be of great significance for future healthcare services.

Prevalence and Treatment of Vulvar Cancer From 2014-2018: A Nationwide Population-Based Study in Korea

BACKGROUND

Vulvar cancer is one of the rare gynecologic malignancies. Despite the recent increasing trend of vulvar cancer in western countries due to the increased infection of human papillomavirus, there has been no study for population-based incidence of vulvar cancer in Korea. We aimed to investigate the prevalence and treatment of vulvar cancer in South Korea between 2014 and 2018.

METHODS

Data from patients diagnosed and treated with vulvar cancer between 2014 and 2018 were obtained from the Health Insurance Review and Assessment Service/National Inpatient Sample (National In-Patient Sample) in South Korea.

RESULTS

A total of 4,636,542 women were identified through the HIRA-NIS database from 2014 to 2018, of which 259 patients were diagnosed and treated for vulvar cancer. The mean age diagnosed with vulvar cancer was 62.82 (± 14.30) years in 2014, 64.19 (± 16.79) years in 2015, and 67.40 (± 14.41) years in 2016. In terms of treatment modalities, the most frequent treatment was surgery only without chemotherapy or radiation therapy. In the age-specific prevalence analysis, vulvar cancer was the most prevalent among those over 70 years old. According to multiple regression analysis, patients' age was significantly associated with the prevalence of vulvar cancer. Vulvar cancer was more prevalent in women with low socioeconomic status (SES) compared to those with high SES in 2018 (OR, 4.242; P < 0.001).

CONCLUSION

Considering the high prevalence of vulvar cancer in the elderly, it is necessary to establish a new strategy for early screening and treatment.

Trends in cervical cancer screening rates among Korean women: results of the Korean National Cancer Screening Survey, 2005–2020

Objective

This study aimed to analyze the trends in cervical cancer screening rates, including organized and opportunistic cancer screening rates, with the Papanicolaou test among Korean women.

Methods

Data were collected from a nationwide, cross-sectional, Korean National Cancer Screening Survey. To evaluate the cervical cancer screening rates, we used the screening approach of “cervical cancer screening rate with recommendation,” defined as the proportion of women who underwent the Papanicolaou test during the previous 2 years according to the Protocol of National Cancer Screening Program for Cervical Cancer in Korea. The joinpoint regression analysis, which describes the annual percent change (APC), was performed to detect significant changes in cervical cancer screening rates in women aged 30-74 years during 2005-2020.

Results

The cervical cancer screening rate was 56.0% in 2020. From 2005 to 2013, there was a rising trend in cervical cancer screening rates (APC=2.70%, 95% confidence interval [CI]:1.05 to 4.38), followed by a falling trend (APC=−2.67%, 95% CI:−4.3 to −1.01). The falling trend was significantly associated with age (≥40 years), education level (below the 15th grade), household income (below the middle-income level), and residence (all residential areas).

Conclusion

The recent falling trend was more common in women with a low socioeconomic status, which suggests that there is a socioeconomic gap in cervical cancer screening. Moreover, young women in their thirties had a low screening rate. Therefore, an active participation strategy for women vulnerable to cervical cancer is required.

We evaluated trends in cervical cancer screening rates in women aged 30–74 years in 2005–2020. The screening rate rose from 57.0% in 2005 to 67.0% in 2013, and then 56.0% in 2020. The falling trend in the screening rate was significantly associated with low household income, low education level, and all residential areas (especially rural areas).

Trends in incidence and survival of patients with vulvar cancer in an Asian country: Analysis of the Korean Central Cancer Registry 1999-2018

OBJECTIVE

To report 20-year trends in incidence and survival of vulvar cancer in Korea.

METHODS

Using data from the Korean Central Cancer Registry, age-standardized incidence rates (ASRs) and annual percentage changes (APCs) were calculated. Net survival (NS) was estimated by the Pohar-Perme method, and conditional net survival (CNS) was calculated.

RESULTS

A total of 2221 patients was diagnosed with vulvar cancer during the 1999-2018 period, with an ASR of 0.32 per 100,000 person-years. Among the cases, 51.4% were squamous cell carcinoma (SqCC), 21.3% were Paget disease, and 8.6% were basal cell carcinoma (BCC). There was an increase in incidence for all vulvar cancer (APC 2.4%, 95% CI 1.8-3.0). However, although BCC (APC 7.0%, 95% CI 3.3-10.8) and Paget disease (APC 5.9%, 95% CI 4.2-7.6) increased, SqCC did not (APC 0.2%, 95% CI -0.8-1.2). There was an increase in incidence in all age groups. The 5Y NS was 74.0% overall, and it did not improve significantly during the study period. The 5Y CNS of vulvar cancer increased continuously with time survived: from 74.0% (71.4-76.4) at baseline to 98.1% (95% CI, 85.4-99.8) at 5 years after diagnosis.

CONCLUSIONS

The incidence of vulvar cancer in Korea showed a different pattern from those in the US and Europe: SqCC incidence was relatively low and remained stable, but the incidence of BCC and Paget's disease increased. Survival did not improve in the past two decades. Patients can be considered cured after surviving for 5 years.

Characteristics and Related Factors of High-Risk Human Papillomavirus Infection in Pregnant Women

Background

Cervical cancer is a risk for women worldwide. The aim of this study was to examine the occurrence of high-risk human papillomavirus (HR-HPV) infection and its related factors in pregnant women and provide a scientific basis for the targeted prevention and treatment of cervical cancer in pregnant women.

Material/Methods

A total of 1774 pregnant women were included, and 1774 non-pregnant women were selected as controls. Cervical exfoliated cells were collected from all women for HR-HPV (AptimaE6, E7mRNA) and ThinPrep cytologic testing, and the vaginal discharge of all pregnant women was tested for pH level and routine pathogenic microorganisms.

Results

The HPV-16-positive and HPV-16/18/45-positive rates in pregnant women were higher than those of non-pregnant women (P<0.05). There was a statistically significant difference in HR-HPV-positive rate, HPV-16-positive rate, and non-HPV-16/18/45-positive rate among pregnant women of different ages (P<0.05). There was a statistically significant difference in HR-HPV-positive rate and non-HPV-16/18/45-positive rate in the first, second, and third trimester (P<0.05). The HR-HPV-positive rate, HPV-16-positive rate, HPV-18/45-positive rate, and non-HPV-16/18/45-positive rate of pregnant women with concurrent infection were higher than those in women without concurrent infection (P<0.05). The HR-HPV-positive and HPV-16/18/45-positive rates in pregnant women were associated with cytologic examination results (P<0.05).

Conclusions

The overall infection rates of HR-HPV-16 and HR-HPV-18/45 in pregnant women were higher than those in non-pregnant women. The gestation period was found to be a susceptible period for infection with HR-HPV, and we recommend the implementation of cervical cancer screening based on HR-HPV testing in pregnant women.

Association between human papillomavirus vaccination and serious adverse events in South Korean adolescent girls: nationwide cohort study

OBJECTIVE

To evaluate the association between human papillomavirus (HPV) vaccination and serious adverse events in adolescent girls in South Korea.

DESIGN

Cohort study.

SETTING

A large linked database created by linking the Korea Immunization Registry Information System and the National Health Information Database, between January 2017 and December 2019.

PARTICIPANTS

441 399 girls aged 11-14 years who had been vaccinated in 2017: 382 020 had been vaccinated against HPV and 59 379 had not been vaccinated against HPV.

MAIN OUTCOME MEASURES

Outcomes were 33 serious adverse events, including endocrine, gastrointestinal, cardiovascular, musculoskeletal, haematological, dermatological, and neurological diseases. A cohort design was used for the primary analysis and a self-controlled risk interval design for the secondary analysis; both analyses used a risk period of one year after HPV vaccination for each outcome. Incidence rate and adjusted rate ratios were estimated using Poisson regression in the primary analysis, comparing the HPV vaccinated group with the HPV unvaccinated group, and adjusted relative risks were estimated using conditional logistic regression in the secondary analysis.

RESULTS

Among the 33 predefined serious adverse events, no associations were found with HPV vaccination in the cohort analysis, including Hashimoto's thyroiditis (incidence rate per 100 000 person years: 52.7 v 36.3 for the vaccinated and unvaccinated groups; adjusted rate ratio 1.24, 95% confidence interval 0.78 to 1.94) and rheumatoid arthritis (incidence rate per 100 000 person years: 168.1 v 145.4 for the vaccinated and unvaccinated groups; 0.99, 0.79 to 1.25), with the exception of an increased risk observed for migraine (incidence rate per 100 000 person years: 1235.0 v 920.9 for the vaccinated and unvaccinated groups; 1.11, 1.02 to 1.22). Secondary analysis using self-controlled risk intervals confirmed no associations between HPV vaccination and serious adverse events, including migraine (adjusted relative risk 0.67, 95% confidence interval 0.58 to 0.78). Results were robust to varying follow-up periods and for vaccine subtypes.

CONCLUSIONS

In this nationwide cohort study, with more than 500 000 doses of HPV vaccines, no evidence was found to support an association between HPV vaccination and serious adverse events using both cohort analysis and self-controlled risk interval analysis. Inconsistent findings for migraine should be interpreted with caution considering its pathophysiology and the population of interest.