Effectiveness of HPV vaccination against the development of high-grade cervical lesions in young Japanese women

Human papillomavirus (HPV) vaccination in Japan

AIM

To review the status of human papillomavirus (HPV) vaccination in Japan from inception to the present, focusing on past and current challenges.

METHODS

Published articles and website content related to HPV vaccination were reviewed.

RESULTS

The Ministry of Health, Labor and Welfare suspended proactive recommendations for HPV vaccination in June 2013 following repeated media reports of girls experiencing adverse events, including chronic pain and walking disturbances, after receiving the HPV vaccine. Despite later recognition of these symptoms as a functional somatic syndrome, HPV vaccine coverage of target girls aged 12 to 16 years in the National Immunization Program (NIP) rapidly decreased to near zero. This suspension of the proactive HPV vaccination recommendation ceased in fiscal year (f-year) 2022, initiating a 3-year catch-up free HPV vaccination period from April 2022 to March 2025 for women born from f-years 1997 to 2005. These drastic changes were driven by established evidence of the effectiveness and safety of HPV vaccines reported from both Japan and other countries, and a nine-valent HPV vaccine has been included in the NIP since f-year 2023. However, the estimated HPV vaccination rate in the NIP remains low at ≤30%.

CONCLUSIONS

To regain high coverage of HPV vaccination in Japan, it is essential that government, industry, and academic society work together to raise awareness and educate Japanese people about cervical cancer prevention and HPV-related diseases.

Exploration of individual socioeconomic and health-related characteristics associated with human papillomavirus vaccination initiation and vaccination series completion among adult females: A comprehensive systematic evidence review with meta-analysis

INTRODUCTION

Human papillomavirus (HPV) vaccination rates among females are lower than the World Health Organization target and vaccination rates specifically among adult females are even much lower.

METHODS

We systematically evaluated individual socioeconomic and health-related characteristics associated with HPV vaccination initiation and vaccination series completion among adult females (PROSPERO: CRD42023445721). We performed a literature search on December 14, 2022, and supplemented the search on August 1, 2023. We pooled appropriate multivariable-adjusted results using an inverse variance random-effects model and expressed the results as odds ratios with associated 95 % confidence intervals. A point pooled significantly increased/decreased odds of 30-69 % was regarded to be strongly associated, and ≥ 70 % was very strongly associated.

RESULTS

We included 63 cross-sectional studies. There were strongly increased odds of vaccination initiation among White women compared with Black or Asian women, and those with higher education, health insurance, a history of sexually transmitted infection (STI), receipt of influenza vaccination in the preceding year, not married/cohabiting, not smoking, using contraception, and having visited a healthcare provider in the preceding year. We observed very strongly increased odds of vaccination initiation among those younger and having been born in the country of study. Similarly, there were strongly increased odds of completing the vaccination series for the same variables as initiating vaccination, except for higher education, prior STI, smoking and contraception use. Additional variables associated with strongly increased odds of vaccination series completion not seen in initiation were higher annual household income, being lesbian/bisexual, and having a primary care physician. We observed very strongly increased odds of vaccination series completion similar to vaccination initiation but including for White compared with Black women, higher education, and prior cervical cancer screening.

CONCLUSIONS

These individual characteristics may be the key to identifying women at increased risk of not being vaccinated against HPV and could inform targeted messaging to drive HPV vaccination.

Cancer literacy differences of basic knowledge, prevention, early detection, treatment and recovery: a cross-sectional study of urban and rural residents in Northeast China

Background

Cancer literacy as a potential health intervention tool directly impacted the success of cancer prevention and treatment initiatives. This study aimed to evaluate the cancer literacy in Northeast China, and explore the factors contributing to urban-rural disparities.

Methods

A cross-sectional survey was conducted in 14 cities across Liaoning Province, China, from August to October 2021, using the multistage probability proportional to size sampling (PPS) method. The survey comprised 4,325 participants aged 15-69 and encompassed 37 core knowledge-based questions spanning five dimensions. Associations between sociodemographic factors and the cancer literacy rate were evaluated using chi-square tests and multivariate logistic regression model.

Results

The overall cancer literacy rate was 66.9% (95% CI: 65.6-68.2%). In the primary indicators, cancer literacy were highest in treatment (75.8, 95% CI: 74.2-77.4%) and early detection (68.2, 95% CI: 66.8-69.6%), followed by basic knowledge (67.2, 95% CI: 65.8-68.6%), recovery (62.6, 95% CI: 60.7-64.5%) and prevention (59.7, 95% CI: 58.2-61.3%). Regarding secondary indicators, the awareness rates regarding cancer-related risk factors (54.7, 95% CI: 52.8-56.5%) and early diagnosis of cancer (54.6, 95% CI: 52.7-56.6%) were notably inadequate. Rural participates exhibited lower cancer literacy across all dimensions compared to urban. Multi-factor analysis showed that factors such as advanced age, limited education or low household income were barriers to health literacy in rural areas.

Conclusion

Strengthening awareness concerning prevention and early detection, particularly among key populations, and bridging the urban-rural cancer literacy gap are imperative steps toward achieving the Healthy China 2030 target.

Etiology, diagnosis, treatment, and prevention of human papilloma virus-associated oropharyngeal squamous cell carcinoma

Classical oropharyngeal squamous cell carcinoma (OPSCC) caused by alcohol consumption and smoking and HPV-associated OPSCC caused by human papillomavirus (HPV) infection have different etiologies, incidences, and prognoses. Therefore, the 8th American Joint committee on Cancer (AJCC) and Union for International Cancer Control (UICC) TNM classifications propose distinguishing HPV-associated OPSCC from classical OPSCC and classifying it as an independent disease. Therefore, this review provides an overview of HPV-associated OPSCC from the perspectives of epidemiology, carcinogenesis, development, diagnosis, treatment, and prevention. The incidence of HPV-associated OPSCC is increasing. Although HPV vaccination has been shown to be effective at reducing the incidence of cervical cancer, it is still unclear how it affects the incidence of HPV-associated OPSCC. Additionally, the prognosis of patients with HPV-associated OPSCC is extremely favorable compared to that of patients with classical OPSCC. Therefore, patients with HPV-associated OPSCC may undergo reduced-dose therapy, although attempts to reduce treatment intensity should be carefully planned to ensure they do not compromise oncological outcomes, and large-scale trials aimed at reducing treatment intensity are ongoing.

Disparities among Japanese municipalities in recommendations for routine and catch-up HPV vaccinations

In November 2021, the government of Japan announced a reversal of its decision in 2013 to suspend the previous proactive recommendation for HPV vaccination. However, the program for young girls to receive routine and catch-up vaccinations has not necessarily developed as expected. We conducted a nationwide questionnaire survey by mail in September 2022. The survey was mailed to 133 municipalities consisting of all cities/wards of the Tokyo and Osaka Prefectures and all other prefectural capital cities. Responses were received from 82 municipalities (62.7%). Notification of routine HPV vaccinations had already been sent to 76 (92.7%) of the municipalities; 70 (85.4%) had been encouraged to promote catch-up vaccinations. The questionnaire forms for registration and pre-vaccination screening for routine immunization had been sent to 74.1% (60/81) of the municipalities and 68.8% (55/80) for catch-up immunizations. For catch-up vaccination, only 54 municipalities (65.9%) had detailed vaccination records for those eligible. In total, 10 municipalities (12.2%) had virtually no vaccination records because these had already been discarded. In addition, 61 municipalities (74.4%) had notified only women and girls eligible for a catch-up vaccination based on their vaccination record, whereas 25.6% (21/82) of the municipalities reported that they had sent, or would send, the notification to all women and girls within the targeted grades, including those who had already been vaccinated with three injections. The survey revealed disparities among the municipalities in their HPV vaccine notification processes. Future research on monitoring HPV vaccination rates and incidence rates of cervical cancer and precancerous lesions in each municipality will be desirable.

Human papillomavirus vaccination and cervical cancer risk

Persistent human papillomavirus infection is the central cause of cervical cancer, the leading cause of cancer death among women worldwide. Clear evidence from both randomized trials and population based studies shows that vaccination against human papillomavirus reduces the incidence of cervical pre-cancer. These data suggest that the vaccine reduces the incidence of cervical cancer. However, human papillomavirus vaccine coverage is inadequate in all countries, especially in low and middle income countries where disease burden is highest. Supply side strategies to improve coverage include increasing the availability of low cost vaccines, school located delivery, single dose vaccine schedules, and development of vaccines that do not need refrigeration. Demand side strategies include enhancing provider recommendations, correcting misinformation, and public awareness campaigns. The near elimination of cervical cancer is achievable through increased uptake of human papillomavirus vaccination and efforts to increase screening for cervical cancer, especially when enacted to reduce disparities in across the world.

Effectiveness of HPV vaccine against cervical precancer in Japan: multivariate analyses adjusted for sexual activity

Japanese girls aged 12–16 years are offered free human papillomavirus (HPV) vaccination and cervical cancer screening is conducted with cytology and not HPV testing from the age of 20 years. So far, no study has analyzed the effect of HPV vaccination against cervical precancers considering HPV infection status and sexual activity. We aimed to analyze the vaccine effectiveness (VE) against HPV infection and cytological abnormalities, adjusted for sexual activity. This study comprised women aged 20–26 years who underwent cervical screening in Niigata. We obtained HPV vaccination status from municipal records and a questionnaire along with information concerning sexual activity. Of 5194 women registered for this study, final analyses included 3167 women in the vaccinated group (2821 vaccinated women prior to sexual debut) and 1386 women in the unvaccinated group. HPV 16/18 (0.2% vs 3.5%), 31/45/52 (3.4% vs 6.6%), and 31/33/45/52/58 (5.0% vs 9.3%) positive rates were significantly lower in the vaccinated group (P < 0.001). No women vaccinated before sexual debut had HPV 16/18‐related cytological abnormalities. VE for HPV 16/18 infection and high‐grade cytological abnormalities in women vaccinated prior to sexual debut were 95.8% (95% CI 81.9–99.0%; P < 0.001) and 78.3% (95% CI 11.3–94.7%; P = 0.033), respectively, in multivariate analyses adjusted for age and number of sexual partners. However, analyses of all vaccinated women did not show significant effectiveness against cytological abnormalities. Our results showed the effectiveness of HPV vaccine against high‐grade cervical cytological abnormalities and the importance of the vaccination before sexual debut.

Impact of a human papillomavirus vaccination programme within organized cervical cancer screening: cohort study

BACKGROUND

We assessed the effectiveness of an HPV vaccination programme in lowering cervical abnormality risk, and conferring herd protection.

METHODS

Retrospective cohort study using linked screening and vaccination administrative health data of the general population of Ancona Province, Italy. We included all female residents born in 1990-1993, eligible for catch-up HPV vaccination up to age 25y, and adhering to organised screening in 2015-2020 (n=4665). Cervical abnormalities rates were compared between: vaccinated and unvaccinated women, and cohorts with high and low vaccination uptake. Analyses were adjusted for age, country of birth, screening tests number, laboratory, and municipality average income. Main outcomes were ASC-US+ or LSIL+ Pap smears, and CIN1+ or CIN2+ histology.

RESULTS

Mean screening age was 26.6{plus minus}1.5 years, and 1,118 screened women (24.0%) were vaccinated (mean vaccination age 19.2{plus minus}1.5 years). The diagnosed cervical abnormalities were: 107 LSIL+ (2.3%), 70 CIN1+ (1.5%), and 35 CIN2+ (0.8%). The adjusted odds ratios of LSIL+, CIN1+ and CIN2+ among vaccinated vs unvaccinated women were, respectively: 0.55 (95% confidence interval 0.33-0.91), 0.43 (0.22-0.86), and 0.31 (0.11-0.91). Among the unvaccinated, those in the highest-uptake (45.3%) 1993 cohort, versus the last pre-vaccination 1990 cohort, showed AORs of LSIL+ and CIN1+ of 0.23 (0.10-0.50), and 0.22 (0.07-0.69), respectively.

CONCLUSIONS

In the first evaluation from Central Italy, catch-up HPV vaccination considerably reduced the risk of all cervical abnormalities diagnosed within organized screening, and conferred an elevated degree of herd protection among unvaccinated women.

IMPACT

The high protection conferred by HPV vaccination suggests the need to update cervical screening.

An Evaluation of Dose-Related HPV Vaccine Effectiveness Using Central Registries in Michigan

BACKGROUND

Human papillomavirus (HPV) vaccine effectiveness (VE) evaluations provide important information for vaccination programs. We established a linkage between statewide central registries in Michigan to estimate HPV VE against in situ and invasive cervical lesions (CIN3+).

METHODS

We linked females in Michigan's immunization and cancer registries using birth records to establish a cohort of 773,193 women with known vaccination history, of whom 3,838 were diagnosed with CIN3+. Residential address histories from a stratified random sample were used to establish a subcohort of 1,374 women without CIN3+ and 2,900 with CIN3+ among continuous Michigan residents. VE and 95% confidence intervals (CI) were estimated using cohort and case-cohort methods for up-to-date (UTD) vaccination and incomplete vaccination with 1 and 2 doses, and stratified by age at vaccination.

RESULTS

Both analytic approaches demonstrated lower CIN3+ risk with UTD and non-UTD vaccination vs. no vaccination. The cohort analysis yielded VE estimates of 66% (95% CI, 60%-71%) for UTD, 33% (95% CI, 18%-46%) for 2 doses-not UTD, and 40% (95% CI, 27%-50%) for 1 dose. The case-cohort analysis yielded VE estimates of 72% (95% CI, 64%-79%) for UTD, 39% (95% CI, 10%-58%) for 2 doses-not UTD, and 48% (95% CI, 25%-63%) for 1 dose. VE was higher for vaccination at age <20 than ≥20 years.

CONCLUSIONS

The statewide registry linkage found significant VE against CIN3+ with incomplete HPV vaccination, and an even higher VE with UTD vaccination.

IMPACT

Future VE evaluations by number of doses for women vaccinated at younger ages may further clarify dose-related effectiveness.

The Lifetime Cost Estimation of Human Papillomavirus-related Diseases in China: A Modeling Study

OBJECTIVES

To estimate the lifetime treatment costs of patients with human papillomavirus (HPV) infection-related diseases in China and to provide cost estimates for the economic evaluation of HPV intervention strategies.

METHODS

We extracted real-world hospital data from 2012 to 2019 and screened for subjects who met the criteria of clinical diagnosis of HPV-related diseases to obtain country-specific inputs into a Markov decision model. The model simulated lifetime treatment costs for HPV from the perspective of a national payer. A 5% discount rate was applied. Costs were converted and inflated to 2020 US dollars (USD).

RESULTS

Using 2021 as the base year, the lifetime costs per patient for carcinoma in situ, local metastasis, and distant metastasis cervical cancer are $24,208 (95%CI: 18,793-30,897), $19,562 (95%CI: 14,456-25,567), and $17,599 (95%CI: 10,604-25,807), respectively. For carcinoma in situ, local metastasis, and distant metastasis vaginal cancer, the lifetime costs are $17,593 (95%CI: 14,962-23,596), $17,120 (95%CI: 13,215-22,417), and $22,411 (95%CI: 12,172-22,249), respectively. The base-case lifetime cost per patient for different stages of vulvar cancer/penile cancer/anal cancer/oral cancer/oropharyngeal cancer/laryngeal cancer falls within $17,120-$58,236.

CONCLUSIONS

Using real-world data, we calculated lifetime treatment costs of HPV-related cancer in China and found that the lifetime cost for patients exceeded $17,000 for various stages of disease. The national burden of HPV-related disease could be significantly reduced by eliminating HPV infection.

The ASCCP Cervical Cancer Screening Task Force Endorsement and Opinion on the American Cancer Society Updated Cervical Cancer Screening Guidelines

ABSTRACT

The American Cancer Society (ACS) released updated cervical cancer screening guidelines in 2020 that endorse a shift in practice to primary human papillomavirus (HPV) screening in people with a cervix, beginning at ages of 25-65 years. When access to US Food and Drug Administration-approved primary HPV testing is not available, the ACS offers cotesting or cytology as acceptable alternative strategies but suggests that these testing modalities may be excluded from future iterations of the guidelines. The ASCCP recognizes the benefits and risks of primary HPV cervical cancer screening while acknowledging the barriers to widespread adoption, including implementation issues, the impact of limited HPV vaccination in the United States, and inclusion of populations who may not be well represented on primary HPV screening trials, such as underrepresented minorities. The ASCCP endorses the 2018 US Preventive Services Task Force Recommendation Statement and supports the ACS cervical cancer screening guidelines. Most importantly, the ASCCP endorses any cervical cancer screening for secondary prevention of cervical cancer and recommends interventions that improve screening for those who are underscreened or unscreened.

Changes and remaining challenges for the Japanese immunization program: Closing the vaccine gap

The Japanese immunization program has made considerable progress since 2009: several new vaccines have been introduced and most are included in the National Immunization Program (NIP). In October 2020, the Japanese law on immunization was revised, which resulted in a few laudable achievements. First, rotavirus vaccines were added to the NIP, 10 years after their introduction, and noteworthy studies of vaccine effectiveness and the incidence of intussusception in Japanese children were published. Second, rules on vaccine intervals-which had been a longstanding concern-were withdrawn. In addition to this revision of the law, the Japanese version of the Vaccine Information Statement (VIS) was released by the Japan Pediatric Society in 2018. The VIS provides useful caregiver information on general immunization concepts and individual vaccines. Further challenges for the Japanese immunization program include (1) administering a booster dose of pertussis-containing vaccine to preschool children or teenagers, (2) reestablishing the active recommendation for human papilloma virus vaccines, (3) adding the mumps and influenza vaccines to the NIP, and (4) ensuring optimal dosing of seasonal influenza vaccines. During the current coronavirus disease 2019 (COVID-19) pandemic, vaccination rates among children have been decreasing in many countries. In Japan, vaccination rates have been stable in infants, but declining among toddlers and school-aged children, despite public awareness of the need for timely administration of vaccines during the pandemic. Clearly, further action is needed if we are to adequately protect children living in Japan from vaccine-preventable diseases.