Bivalent Human Papillomavirus Vaccine Effectiveness in a Japanese Population: High Vaccine-Type-Specific Effectiveness and Evidence of Cross-Protection

HPV Vaccine Issues in Japan: A review of our attempts to promote the HPV vaccine and to provide effective evaluation of the problem through social-medical and behavioral-economic perspectives

In Japan, subsidies from local and national government programs for HPV vaccination of girls aged 13-16 began in 2010. By 2013, HPV vaccines were being used routinely for vaccinating girls aged 12-16 as part of its national immunization program. However, in June of 2013, in response to reports of possible adverse reactions to the vaccine, Japan's Ministry of Health, Labor, and Welfare (MHLW) announced a 'temporary suspension' of its governmental recommendation for HPV vaccination. The vaccination rate quickly dropped from 70 % of age-eligible girls to almost zero. It was not until 2021 that the government's recommendation suspension finally ended. The efficacy and safety of the HPV vaccine is now well documented, yet Japan has failed to reestablish any credible level of HPV vaccination. The World Health Organization (WHO) warned that Japan's HPV vaccination debacle was likely to result in real harm to the girls who lacked its protection; something we have already demonstrated with real-world data. To reinvigorate the HPV vaccination program in Japan to its prior levels, in the face of the current high level of HPV vaccine hesitancy, we will have to address the irrationality of human decision-making pointed out by behavioral economics. The Japanese government must act expeditiously to promote stronger cervical cancer control measures.

How has post-implementation surveillance of high-coverage vaccination with HPV16/18-AS04 vaccine in England added to evidence about its cross-protective effects?

BACKGROUND

Bivalent human papillomavirus HPV16/18-AS04 vaccine (Cervarix, GSK) offers direct protection against HPV16/18. Results from randomised controlled trials showed cross protective effects and suggested that declines in some closely related HPV types could be expected in a population with high vaccination coverage.

AIM

To evaluate the evidence for cross-protection afforded by HPV16/18-AS04 from post-implementation surveillance in England, and how this complements clinical trial data and post-implementation observations in other countries.

METHODS

Evidence of cross-protection in young women offered vaccination with HPV16/18-AS04 was gathered from HPV surveillance in England. Data from clinical trials and other post-implementation studies were reviewed.

RESULTS

Surveillance using anonymised residual specimens in England found declines of 52.3%, 67.4% and 33.3% against grouped HPV-31/33/45 in 16-18, 19-21, and 22-24 year olds, respectively. Additionally, type-specific analysis found that the prevalence of HPV31 declined to below 1% across all age groups. Cross-protection has been monitored and maintained for over 10 years since the introduction of the vaccination programme. Cross-protection against HPV6/11 was not found in English surveillance outcomes.

CONCLUSION

Surveillance of type-specific infections in vaccine-eligible populations in England has generated clear evidence of cross-protective effects from HPV16/18-AS04 vaccination against high-risk HPV 31/33/45 infections, consistent with other post-implementation observations and confirming and in some ways exceeding expectations from clinical trials.

Questionnaire survey on cervical cancer screening and HPV awareness among patients at a local cancer center in Japan

BACKGROUND

The incidence of cervical intraepithelial neoplasia is increasing in Japan. Although human papillomavirus (HPV) vaccination and cancer screening are crucial in preventing cancer-related mortality, the cervical cancer screening rate in Japan was only approximately 43.6% in 2022. This study aimed to conduct an epidemiological analysis of cervical cancer by collecting data from individual patients.

METHODS

A questionnaire survey was administered to patients who visited our hospital between January 2017 and July 2023 owing to abnormal cervical cytological findings or a cancer diagnosis. Patients answered questions regarding their history of cervical cancer screening as well as their knowledge of HPV and cervical cancer.

RESULTS

During the study period, 471 patients participated in the survey, with 35 declining to participate. Patients with Stage 1b1-4b primarily sought medical attention due to self-reported symptoms (P < 0.001); however, they were less likely to have undergone cervical cancer screening (P < 0.001). Additionally, older patients were less likely to be aware of the association of HPV with cervical and other cancers. Notably, 28 of the 129 patients with stage 1b1-4b cancer underwent cervical cancer screening within 2 years. The tumor location within the endocervical canal emerged as a significant factor contributing to the difficulty for an accurate diagnosis of precancerous or cervical cancer during cervical screening. Furthermore, non- squamous cell carcinoma (SCC) histology was another possible factor.

CONCLUSIONS

Our findings suggest the need to widely disseminate information regarding the significance of cancer screening to increase cancer screening rates. Moreover, establishing strategies for improving the accuracy of detecting lesions during screening for non-SCC and endocervical canal tumors is crucial.

Estimation of self-funded human papillomavirus vaccine recipients from Japan's previously assumed "unvaccinated generation"

Precise vaccination data is essential to accurately estimate the effectiveness of the human papillomavirus (HPV) vaccine against HPV-related cancers. In Japan, the number of subsidized HPV vaccinations can be tracked through registries, but the number of self-funded vaccinations has not been tracked. The number of individuals who chose to receive the vaccine at their own expense, despite being ineligible for public subsidies due to their age, is unknown and has been nominally considered to be zero. Our aim is to produce a more accurate estimate of this number using recently released proprietary data. First, we estimated the total number of self-funded HPV vaccinations occurring from 2010 to 2012 using public data from the Ministry of Health, Labour and Welfare and our previously reported data on the number of HPV vaccinations eligible for public subsidy. Second, using proprietary data from the vaccine manufacturer, we calculated the distribution of self-funded vaccination shots by age. Finally, we combined these data to estimate the number of self-funded HPV vaccinations by birth fiscal year (FY) relative to a yearly reference population. We found that 78,264 individuals born in FY1993 and 58,190 born in FY1992 self-funded their vaccinations, representing 13.6% and 10.0% of the reference population, respectively. Additionally, we found that 5%-10% of individuals born from FY1986 to FY1991 self-funded their vaccinations. Our study revealed for the first time that a certain number of individuals from the "HPV unvaccinated generation," ineligible for subsidies due to age restrictions, chose to self-fund their vaccinations.

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.

Effectiveness of prophylactic HPV vaccines against cervical abnormalities and HPV infection in Japan: The J-HERS 2021 multicenter study

This study investigated the efficacy of the prophylactic human papillomavirus (HPV) vaccine, which was initiated between 2009 and 2013 in Japan. The study involved 1529 eligible women aged 16-39 years who visited 11 outpatient clinics in Japan for various reasons. These patients underwent HPV genotype analysis and a Pap test of cervical cell samples. A total of 299 women (19.6%) had received the prophylactic HPV vaccine (bivalent:quadrivalent vaccine ratio = 2:1). Of the 5062 participants in the Japanese Human Papillomavirus Disease Education and Research Survey (J-HERS 2011), which was conducted in the pre-vaccination era, 3236 eligible participants were included as controls. In this study (J-HERS 2021), the highest rate of HPV vaccination (53%) was observed in patients aged 22-27 years. Vaccinated individuals exhibited a 49% rate of protection against low-grade intraepithelial lesions (LSILs) and atypical squamous cells, not excluding high-grade squamous intraepithelial lesions (ASCH) or worse (LSIL/ASCH+), and a 100% rate of protection against high-grade squamous intraepithelial lesions (HSILs) or worse (HSIL+). Significant reductions in HPV16 (95%) and HPV18 (100%) infections were noted, but no differences were observed in HPV6 and HPV11 infections. The prevalences of HPV51 and HPV59 increased with vaccination, although these changes were not confirmed in the comparative study with J-HERS 2011. Comparing the prevaccination (J-HERS 2011) and postvaccination (J-HERS 2021) periods, 43%, 51%, 88%, and 62% reductions in HPV16, HPV18, HPV16/18, and HPV31/58 infection rates were observed, respectively. Similarly, 62% and 71% reductions in LSIL/ASCH+ and HSIL+ rates were noted, respectively. There were 88% and 87% reductions in LSIL/ASCH+ and HSIL+ rates in 16-21- and 28-33-year-old patients, respectively. Bivalent or quadrivalent vaccines provided 100% protection against high-grade squamous cell lesions (suggestive of CIN2 or CIN3) in young women aged <39 years at 9-12 years after initiation of Japan's first nationwide HPV vaccination program. Cross-protection against HPV31 and HPV58 is likely to occur, although some HPV-type replacements are inconsistent across vaccination regimens. This demonstrates the effectiveness of the HPV vaccine. However, continuous monitoring of cervical cancer and precancer is necessary in younger generations (born 1997-2007), who were rarely vaccinated due to the prolonged suspension of the vaccine recommendations in Japan.

Effectiveness of quadrivalent HPV vaccination in reducing vaccine-type and nonvaccine-type high risk HPV infection

This study aimed to assess human papillomavirus (HPV) vaccine effectiveness (VE) against both vaccine-type and nonvaccine-type high-risk HPV (hrHPV) infection, and duration of protection in United States. The study population was female participants aged 18-35 years with an HPV vaccination history and genital testing for HPV from the National Health and Nutrition Examination Survey, 2007-2016. Participants vaccinated before sexual debut were assessed against 13 nonvaccine-type hrHPV infection including 31/33/35/39/45/51/52/56/58/59/68/73/82. Multivariable logistic regression was used to estimate VE overall, by age at diagnosis, time since vaccination and lifetime sexual partners. A total of 3866 women were included in the analysis, with 23.3% (95% CI 21.3%-25.4%) having been vaccinated (≥1 dose). VE against vaccine-type HPV18/16/11/6 infection was 58% overall, which was mainly driven by those aged 18-22 years (VE = 64%) and 23-27 years (65%). Among participants aged 18-22 years vaccinated before sexual debut, the VE was 47% (23%-64%) against 13 nonvaccine-type hrHPV and 61% (95% CI 36%-77%) against 5 selected nonvaccine-type hrHPV35/39/52/58/59. Both direct effectiveness and cross-protection maintained effective for 5-10 years post vaccination. We also found the prevalence of ever diagnosed cervical cancer among vaccinated was significantly lower (0.46%, 4/874) than that among unvaccinated participants (1.27%, 38/2992). These findings highlight the potential of significant reduction of cervical cancer following the universal HPV vaccination programme.

A novel C-terminal modification method enhanced the yield of human papillomavirus L1 or chimeric L1-L2 virus-like particles in the baculovirus system

Human papillomavirus (HPV) major capsid protein L1 virus-like particles (VLPs) produced in the baculovirus system showed excellent safety and immunogenicity, but the relatively high production cost stands as a substantial barrier to extensive commercialization, especially in producing multivalent vaccines. Here, a novel method, C-terminal basic amino acid (aa) substitution, was developed for increasing VLP and chimeric VLP (cVLP) production in this system. A series of mutants of five HPV types, including three L1 VLPs (6L1, 11L1, and 52L1) and two L1-L2 cVLPs (16L1-33L2, 58L1-16L2), were constructed. We found that most mutants exhibited higher protein expression in Sf9 cells, among which the yields of the superior mutants, 6L1CS4, 11L1CS3, 52L1m4∆N13CS1, 16L1-33L2 CS1, and 58L1-16L2 CS3, were up to 40, 35, 20, 35, and 60 mg/L, which respectively increased by 4.2-, 7.3-, 5-, 2.5-, and 3.4-fold, and they also showed robust immunogenicity and great stabilities. Additionally, we found that the increased level of steady-state mRNA may play a crucial role in promoting L1 protein expression. Our results demonstrated that this novel method was cost-effective and can be used to reduce the production costs of L1 VLPs and L1-L2 cVLPs to develop broadly protective and affordable multivalent HPV vaccines.

Prevalence of Human Papillomavirus Types 16/18 and Effect of Vaccination among Japanese Female General Citizens in the Vaccine Crisis Era

The Japanese government withdrew its recommendation for human papillomavirus (HPV) vaccination in June 2013 and resumed it in April 2022. This period is known as the vaccine crisis in Japan. This study aimed to elucidate the prevalence and genotype distribution of HPV among Japanese female citizens, and the effect of vaccination against HPV-16/18 in the era of the vaccine crisis. We recruited Japanese female citizens and asked them to provide self-collected samples from the vaginal wall using cotton swabs for HPV genotyping. Furthermore, we collected the participants' characteristics, including lifestyle and experience of vaccination against HPV, to determine the significant association with HPV infection. HPV-16/18 positivity was found in 5.6% (115/2044) of participants. The highest vaccination rate was observed in the age group of 20-24 years (60.6%), whereas the lowest HPV-16/18 positivity was observed in the age group of 45-49 years (2.8%), followed by the age group of 20-24 years (4.0%). Experience with HPV vaccination significantly reduced the risk of HPV-16/18 infection (adjusted odds ratio, 0.047; 95% confidence interval, 0.011-0.196). Vaccinated women were much less likely to be infected by HPV-16/18, regardless of the HPV vaccine type or the vaccination dose.

Efficacy of prophylactic human papillomavirus vaccines on cervical cancer among the Asian population: A meta-analysis

Objective

We conducted a meta-analysis to assess the efficacy of prophylactic human papillomavirus (HPV) vaccines against cervical cancer precursors and HPV persistent infection among Asian populations.

Methods

Randomized controlled clinical trials conducted in Asian countries were identified from three electronic databases (PubMed, EMBASE and the Cochrane Library). Publication retrieval was performed on September 1, 2022 and only those written in English were included. The data were analyzed with Cochrane Review Manager (version 5.3) and Stata/SE (15.1). Effect sizes were presented as risk ratios (RRs) and 95% confidence intervals (CIs).

Results

Ten articles were considered in the meta-analysis, without significant heterogeneity among them. The fixed-effect RRs and 95% CIs for cervical intraepithelial neoplasia grade 1 (CIN1+) and CIN2+ were 0.10 (0.05–0.21) and 0.11 (0.04–0.27), respectively. Positive effect of HPV vaccination on 6- and 12-month persistent infection were observed, with the respective pooled RRs of 0.05 (95% CI: 0.03–0.09) and 0.09 (95% CI: 0.05–0.15). HPV vaccination has a positive effect on the incidence of cytological abnormalities associated with HPV 16/18 (RR, 0.13; 95% CI (0.09–0.20)). Positive effects of HPV vaccination were also observed for HPV 16- and 18-specific immunogenicity (RR, 235.02; 95% CI (82.77–667.31) and RR, 98.24; 95% CI (50.36–191.67), respectively). Females receiving an initial vaccination showed significant decreased incidences of cervical intraepithelial neoplasia, HPV persistent infection and cytological abnormalities and a significantly higher antibody positive conversion rate compared with non-vaccination counterparts.

Conclusion

Prophylactic HPV vaccines are highly efficacious in preventing cervical cancer in Asian females. The government should accelerate the processes of vaccine introduction and vaccination implementation by prioritizing them in public health policies, which should be helpful to enhance Asian females’ awareness of receiving HPV vaccination volitionally.

Vaccine Hesitancy in Japan: From a Perspective on Medical Uncertainty and Trans-Scientific Theory

The development and dissemination of vaccines has made immunization possible and has led to the successful control and eradication of various infectious diseases in many parts of the world. However, even when vaccines that are said to be "effective" are offered, a certain number of people do not receive them, and this has become a problem known as "vaccine hesitancy". ItThe reason of "Vaccine hesitancy" is pointed out that there is not only because of the risk of contracting infectious diseases if they are not vaccinated, but also because of the lack of a collective immunity system. Vaccines are an effective means of acquiring immunity, but no matter how highly effective vaccines are developed, if the vaccination rate does not exceed a certain number, "herd immunity", which means that the risk of person-to-person transmission is reduced when a significant portion of the population becomes immune to, cannot be acquired. Therefore, how to increase the vaccination rate of the population is a major public health challenge. This paper reviews previous studies on "vaccine hesitancy" in Japan and analyzes people's hesitancy in terms of negative "rumors" about vaccines, risk perception of vaccine side effects, and sense of burden when receiving vaccinations. Then, the author will examine that the background of "vaccine hesitancy" is not only distrust of vaccines and risk perception of side effects, but also distrust of those who provide and promote vaccinations, such as medical professionals, government, and public administration. By using medical uncertainty which shows there are many unknowns and uncertainties in medicine and trans-scientific theory which indicates there are areas that science cannot answer this paper argues that the problem of "vaccine hesitancy" can be reduced if medical professionals and governments show sincere empathy and attitude toward victims of adverse vaccine reactions and those who hesitate to vaccinate.

Vaccine Hesitancy in Japan: From a Perspective on Medical Uncertainty and Trans-Scientific Theory

The development and dissemination of vaccines has made immunization possible and has led to the successful control and eradication of various infectious diseases in many parts of the world. However, even when vaccines that are said to be "effective" are offered, a certain number of people do not receive them, and this has become a problem known as "vaccine hesitancy". Why is vaccine hesitancy a problem? It has been pointed out that the reason is not only because of the risk of contracting infectious diseases if they are not vaccinated, but also because of the lack of a collective immunity system. Vaccines are an effective means of acquiring immunity, but no matter how highly effective vaccines are developed, if the vaccination rate does not exceed a certain number, herd immunity cannot be acquired. Therefore, it is said that how to increase the vaccination rate of the population is a major public health challenge. Hence, the large number of people who do not receive vaccinations due to "vaccine hesitancy" is problematic. This paper reviews previous studies on "vaccine hesitancy" in Japan and analyzes people's hesitancy in terms of negative "rumors" about vaccines, risk perception of vaccine side effects, and sense of burden when receiving vaccinations. Then, I will examine that the background of "vaccine hesitancy" is not only distrust of vaccines and risk perception of side effects, but also distrust of those who provide and promote vaccinations, such as medical professionals, government, and public administration. By using medical uncertainty and trans-scientific theory, this paper argues that the problem of "vaccine hesitancy" can be reduced if medical professionals and governments show sincere empathy and attitude toward victims of adverse vaccine reactions and those who hesitate to vaccinate.

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.

Long-term effectiveness of HPV vaccination against HPV infection in young Japanese women: real-world data

In Japan, public funding for HPV vaccination began in 2010 for girls aged 13–16 years (birth cohort years 1994–1997) and women born in 1994 who turned 25 in 2019. We aimed to verify the long‐term effectiveness of the bivalent HPV vaccine in women aged 25 years. Subjects were women aged 25–26 years who underwent cervical cancer screening and HPV testing in Niigata from 2019 to 2020 (birth cohort years 1993–1994). Information on vaccination status and sexual behavior was obtained from a questionnaire and municipal records. We compared the HPV infection rates of the vaccinated and unvaccinated groups. Of the 429 registrants, 150 (35.0%) and 279 (65.0%) were vaccinated and unvaccinated, respectively. The average period from HPV vaccination to HPV testing was 102.7 months (8.6 years), with a median of 103 months (range 92–109 months). The HPV high‐risk infection rate was 21.3% (32/150) in the vaccinated group and 23.7% (66/279) in the unvaccinated group (P = 0.63). The HPV16/18 infection rate was 0% (0/150) in the vaccinated group and 5.4% (15/279) in the unvaccinated group, showing a significant difference (P = 0.0018), and the vaccine effectiveness was 100%. The cross‐protective type HPV31/45/52 infection rate in the vaccinated group was significantly lower than that in the unvaccinated group (3.3% vs. 10.0%, P = 0.013). There was no significant difference in the mean age at sexual debut and the number of previous sexual partners between the two groups. We have demonstrated the long‐term 9‐year effectiveness of the bivalent vaccine against HPV infection for the first time in Japan.

Changes in HPV16/18 Prevalence among Unvaccinated Women with Cervical Intraepithelial Neoplasia in Japan: Assessment of Herd Effects following the HPV Vaccination Program

Since the human papillomavirus (HPV) vaccination program for Japanese girls aged 12–16 years began in 2010, vaccination uptake has been low in women born before 1993 but high (approximately 70%) in those born during 1994–1999. We previously compared the prevalence of vaccine types HPV16 and HPV18 in cervical intraepithelial neoplasia grade 1–3 (CIN1–3) or adenocarcinoma in situ (AIS) between vaccinated and unvaccinated cohorts and found direct protection effects among vaccinated women in Japan. In this study, we focused on changes in HPV16/18 prevalence among “unvaccinated” cohorts with CIN/AIS. We analyzed HPV16/18 prevalence among 5051 unvaccinated women aged <40 years, newly diagnosed with CIN/AIS during 2012–2021 for time trends. Declining trends in HPV16/18 prevalence over 9 years were observed in CIN1 (36.0–10.0%, Ptrend = 0.03) and CIN2–3/AIS (62.5–36.4%, Ptrend = 0.07) among women aged <25 years. HPV16/18 prevalence in CIN1 and CIN2–3/AIS diagnosed at age 20–24 years was lower in 1994–1999 birth cohorts compared with 1988–1993 birth cohorts (4.5% vs. 25.7% for CIN1 and 40.0% vs. 58.1% for CIN2–3/AIS, both p = 0.04). Significant reduction in HPV16/18 prevalence among young unvaccinated women with CIN1 and CIN2–3/AIS suggests herd effects of HPV vaccination in Japan.

HPV vaccine effectiveness by age at first vaccination among Japanese women

In Japan, the National Immunization Program against human papillomavirus (HPV) targets girls aged 12‐16 years, and catch‐up vaccination is recommended for young women up to age 26 years. Because HPV infection rates increase soon after sexual debut, we evaluated HPV vaccine effectiveness by age at first vaccination. Along with vaccination history, HPV genotyping results from 5795 women younger than 40 years diagnosed with cervical intraepithelial neoplasia grade 2‐3 (CIN2‐3), adenocarcinoma in situ (AIS), or invasive cervical cancer were analyzed. The attribution of vaccine‐targeted types HPV16 or HPV18 to CIN2‐3/AIS was 47.0% for unvaccinated women (n = 4297), but 0.0%, 13.0%, 35.7%, and 39.6% for women vaccinated at ages 12‐15 years (n = 36), 16‐18 years (n = 23), 19–22 years (n = 14), and older than 22 years (n = 91), respectively, indicating the greater effectiveness of HPV vaccination among those initiating vaccination at age 18 years or younger (P < .001). This finding was supported by age at first sexual intercourse; among women with CIN2‐3/AIS, only 9.2% were sexually active by age 14 years, but the percentage quickly increased to 47.2% by age 16 and 77.1% by age 18. Additionally, the HPV16/18 prevalence in CIN2‐3/AIS was 0.0%, 12.5%, and 40.0% for women vaccinated before (n = 16), within 3 years (n = 8), and more than 3 years after (n = 15) first intercourse, respectively (P = .004). In conclusion, our data appear to support routine HPV vaccination for girls aged 12‐14 years and catch‐up vaccination for adolescents aged 18 years and younger in Japan.

Human Papillomavirus Vaccine Efficacy and Effectiveness against Cancer

Human papillomavirus (HPV) is the most common sexually transmitted infection, with 15 HPV types related to cervical, anal, oropharyngeal, penile, vulvar, and vaginal cancers. However, cervical cancer remains one of the most common cancers in women, especially in developing countries. Three HPV vaccines have been licensed: bivalent (Cervarix, GSK, Rixensart, Belgium), quadrivalent (Merck, Sharp & Dome (Merck & Co, Whitehouse Station, NJ, USA)), and nonavalent (Merck, Sharp & Dome (Merck & Co, Whitehouse Station, NJ, USA)). The current HPV vaccine recommendations apply to 9 years old and above through the age of 26 years and adults aged 27–45 years who might be at risk of new HPV infection and benefit from vaccination. The primary target population for HPV vaccination recommended by the WHO is girls aged 9–14 years, prior to their becoming sexually active, to undergo a two-dose schedule and girls ≥ 15 years of age, to undergo a three-dose schedule. Safety data for HPV vaccines have indicated that they are safe. The most common adverse side-effect was local symptoms. HPV vaccines are highly immunogenic. The efficacy and effectiveness of vaccines has been remarkably high among young women who were HPV seronegative before vaccination. Vaccine efficacy was lower among women regardless of HPV DNA when vaccinated and among adult women. Comparisons of the efficacy of bivalent, quadrivalent, and nonavalent vaccines against HPV 16/18 showed that they are similar. However, the nonavalent vaccine can provide additional protection against HPV 31/33/45/52/58. In a real-world setting, the notable decrease of HPV 6/11/16/18 among vaccinated women compared with unvaccinated women shows the vaccine to be highly effective. Moreover, the direct effect of the nonavalent vaccine with the cross-protection of bivalent and quadrivalent vaccines results in the reduction of HPV 6/11/16/18/31/33/45/52/58. HPV vaccination has been shown to provide herd protection as well. Two-dose HPV vaccine schedules showed no difference in seroconversion from three-dose schedules. However, the use of a single-dose HPV vaccination schedule remains controversial. For males, the quadrivalent HPV vaccine possibly reduces the incidence of external genital lesions and persistent infection with HPV 6/11/16/18. Evidence regarding the efficacy and risk of HPV vaccination and HIV infection remains limited. HPV vaccination has been shown to be highly effective against oral HPV type 16/18 infection, with a significant percentage of participants developing IgG antibodies in the oral fluid post vaccination. However, the vaccines’ effectiveness in reducing the incidence of and mortality rates from HPV-related head and neck cancers should be observed in the long term. In anal infections and anal intraepithelial neoplasia, the vaccines demonstrate high efficacy. While HPV vaccines are very effective, screening for related cancers, as per guidelines, is still recommended.

The efficacy of human papillomavirus vaccination in young Japanese girls: the interim results of the OCEAN study

Human papillomavirus (HPV) vaccine has been used to prevent chronic HPV infection, which accounts for cervical cancer. Japanese Ministry of Health, Labor and Welfare (MHLW) conducted an HPV vaccination campaign in 2010 and the Obstetrical Gynecological Society of Osaka initiated a multicenter, prospective cohort study in Osaka, Japan – OCEAN (Osaka Clinical resEArch of HPV vacciNe) study – to investigate the oncogenic HPV prevalence and the long-term protection rate of HPV vaccine. A total of 2814 participants were enrolled on their visit for HPV vaccination between 12 and 18 years old. Among them, 102 participants received HPV/Pap co-test as primary cancer screening at the age of 20–21. We compared the prevalence in two groups (the vaccinated and the unvaccinated group). HPV infection ratio was significantly lower in the vaccinated group compared to the unvaccinated (12.9% vs. 19.7%; p = .04). In particular, HPV 16 and 18 were not detected in the vaccinated group, while 4.9% of participants in the unvaccinated group were infected (p = .001), suggesting that vaccination provided effective protection against high-risk types of HPV. The cross-protection effect of HPV vaccines was also observed against HPV 31, 45, and 52. Although HPV vaccines were not contributed to the reduction of cervical intraepithelial neoplasia 1 (CIN) (p = .28), CIN2 or worse was not observed in vaccinated group. Our research showed that at the age of 20–21, HPV vaccine inhibited the infection of high-risk HPV and had impacted on the development to CIN2 or worse in Japan.

Effectiveness of various human papillomavirus vaccination strategies: A community randomized trial in Finland

INTRODUCTION

We conducted a community-randomized trial (NCTBLINDED) in Finland to assess gender-neutral and girls-only vaccination strategies with the AS04-adjuvanted human papillomavirus (HPV)-16/18 (AS04-HPV-16/18)vaccine.

METHODS

Girls and boys (12-15 years) were invited. We randomized 33 communities (1:1:1 ratio): Arm A: 90% of randomly selected girls and boys received AS04-HPV-16/18 vaccine and 10% received hepatitis B vaccine (HBV); Arm B: 90% of randomly selected girls received AS04-HPV-16/18 vaccine, 10% of girls received HBV, and all boys received HBV; Arm C: all participants received HBV. Effectiveness measurements against prevalence of HPV-16/18 cervical infection were estimated in girls at 18.5 years. The main measures were: (1) overall effectiveness comparing Arms A or B, regardless of vaccination status, vs Arm C; (2) total effectiveness comparing AS04-HPV-16/18 vaccinated girls in pooled Arms A/B vs Arm C; (3) indirect effectiveness (herd effect) comparing girls receiving HBV or unvaccinated in Arm A vs Arm C. Co-primary objectives were overall effectiveness following gender-neutral or girls-only vaccination.

RESULTS

Of 80,272 adolescents invited, 34,412 were enrolled. Overall effectiveness was 23.8% (95% confidence interval: -19.0, 51.1; P = 0.232) with gender-neutral vaccination. Following girls-only vaccination, overall effectiveness was 49.6% (20.1, 68.2; P = 0.004). Total effectiveness was over 90% regardless of vaccination strategy. No herd effect was found. Immunogenicity of the AS04-HPV-16/18 vaccine was high in both sexes.

CONCLUSIONS

This study illustrates the difficulty in conducting community randomized trials. It is not plausible that vaccinating boys would reduce overall effectiveness, and the apparent lack of herd effect was unexpected given findings from other studies. This analysis was likely confounded by several factors but confirms the vaccine's high total effectiveness as in clinical trials.

Effect of a Brief Web-Based Educational Intervention on Willingness to Consider Human Papillomavirus Vaccination for Children in Japan: Randomized Controlled Trial

Background

The human papillomavirus (HPV) vaccination rate in Japan has fallen to nearly zero since the suspension of governmental proactive recommendations in 2013, owing to the development of purported adverse events.

Objective

This study aimed to evaluate the effects of a brief web-based educational intervention using the theory of behavioral insights on the willingness of adults to consider the HPV vaccine for their daughters and sons.

Methods

We recruited 1660 participants aged 20 years or older in March 2018 via a webpage and provided them with a 10-item questionnaire related to the following aspects: awareness regarding HPV infection and vaccination, willingness for immunization, and actions for prevention. We randomly stratified participants based on sex and age with or without a brief educational intervention involving scientific information presented in an easy-to-read format.

Results

Only 484 (29.2%) of the respondents were aware of the benefits of HPV vaccination. Although only 352 (21.2%) of the respondents displayed a willingness for immunization of their daughters, there were 40 (4.8%) more respondents in the intervention group with this willingness (adjusted odds ratio [aOR] 1.32, 95% CI 1.04-1.69). In a subanalysis, the willingness toward vaccination for daughters in men was significantly higher in the intervention group (aOR 1.46, 95% CI 1.05-2.02). However, such a difference was not observed among women (aOR 1.20, 95% CI 0.83-1.73).

Conclusions

This study suggests that a brief web-based educational intervention increases the willingness of adults to consider the HPV vaccine for their children, especially among men. Thus, providing adequate information to men may be a useful strategy to improve the currently low rates of HPV vaccination.

Trial Registration

UMIN Clinical Trials Registry UMIN000049745 (UMIN-CTR); https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000049745

The road to cervical cancer elimination in Malaysia: Evaluation of the impact and cost-effectiveness of human papillomavirus screening with self-collection and digital registry support

The WHO has launched a global strategy to eliminate cervical cancer through the scale‐up of human papillomavirus (HPV) vaccination, cervical screening, and cervical cancer treatment. Malaysia has achieved high‐coverage HPV vaccination since 2010, but coverage of the existing cytology‐based program remains low. Pilot studies found HPV self‐sampling was acceptable and effective, with high follow‐up rates when a digital registry was used, and recently the Malaysian Government announced plans for a national HPV‐based screening program. We therefore evaluated the impact of primary HPV screening with self‐collection in Malaysia in the context of Malaysia's existing vaccination program. We used the “Policy1‐Cervix” modeling platform to assess health outcomes, cost‐effectiveness, resource use and cervical cancer elimination timing (the year when cervical cancer rates reach four cases per 100 000 women) of implementing primary HPV testing with self‐collection, assuming 70% routine‐screening coverage could be achieved. Based on available data, we assumed that compliance with follow‐up was 90% when a digital registry was used, but that compliance with follow‐up would be 50‐75% without the use of a digital registry. We found that the current vaccination program would prevent 27 000 to 32 200 cervical cancer cases and 11 700 to 14 000 deaths by 2070. HPV testing with a digital registry was cost‐effective (CER = $US 6953‐7549 < $US 11 373[<1×GDP per capita]) and could prevent an additional 15 900 to 17 800 cases and 9700 to 10 600 deaths by 2070, expediting national elimination by 11 to 20 years, to 2055 to 2059. If HPV screening were implemented without a digital registry, there would be 1800 to 4900 fewer deaths averted by 2070 and the program would be less cost‐effective. These results underline the importance of HPV testing as a key elimination pillar in Malaysia.

Ten-year questionnaire study on human papillomavirus vaccination targeting new female medical school students: Follow-up to the 2015 report

AIM

We aimed to conduct a fixed-point observation questionnaire survey of changes in young women's human papillomavirus (HPV) vaccination status over the course of 10 years. We also investigated the influence of suspension of governmental recommendation for HPV vaccination since June 2013.

METHODS

During 2011-2020, we conducted a self-completed questionnaire survey among newly enrolled female medical school students in Yokohama, Japan. The questionnaire featured items regarding HPV vaccination status, age, previous sex education, and knowledge about cervical cancer and HPV vaccination.

RESULTS

HPV vaccine uptake rates in 2011 (5.4%) and 2012 (13.5%), when vaccination was self-funded, increased after 2013 (48.7%), when vaccination fees were subsidized. The rate dropped drastically in 2019 (14.3%) and 2020 (5.1%), after suspension of recommendation by the government. Comparisons between new students in 2015/2016, who had high vaccination rates (65.2%), and new students in 2019/2020, who had low vaccination rates (9.8%), showed decreased levels of HPV vaccination awareness, with fewer students having covered cervical cancer prevention in sex education and with respondents having less knowledge about the details of HPV vaccination.

CONCLUSIONS

After the suspension of proactive HPV vaccine recommendation, markedly fewer students have been vaccinated against HPV, even those at the vaccination target age. This situation has substantially influenced the lower awareness about cervical cancer prevention, even among medical school students. To protect young women from cervical cancer in Japan, it is crucial for the government to resume proactive recommendation of HPV vaccines as soon as possible.

A nationwide birth year-by-year analysis of effectiveness of HPV vaccine in Japan

In Japan, the age‐adjusted incidence of cervical cancer has been increasing constantly and rapidly among younger women. We set out to accurately confirm the effectiveness of the HPV vaccine in Japan. Data were collected for women born in the fiscal year (FY) 1990 to 1997, who became eligible for their 20‐y‐old cervical cancer screening between the FY 2010 to 2017. The adjusted incidence of cervical intraepithelial neoplasia (CIN)1+ in women born in FY 1990 to 1993, that is those who reached the national vaccination target age prior to the introduction of publicly subsidized HPV vaccinations, referred here after as “the pre‐introduction generation”, was 1.42% (242/17 040). The incidence in the “vaccination generation” (women born in FY 1994 to 1997, that is those who were heavily vaccinated as a group when they were of the nationally targeted age of 13‐16) was 1.66% (135/8020). There was no significant difference between these incidence rates. However, our FY birth year‐by‐year analysis revealed that the incidence of CIN1+ was obviously lower than that predicted based on just the trend for CIN1+ seen in the pre‐introduction generation. Our analysis revealed that the incidence of CIN3+ was obviously lower in the vaccination generation than in the pre‐introduction generation (P = .0008). The incidence of CIN was already tending to increase in both the pre‐introduction and vaccination generations. The changes in CIN incidence by individual birth FY must be examined to accurately determine the actual effects of the HPV vaccine for reducing mild cervical lesions.

Understanding confidence in the human papillomavirus vaccine in Japan: a web-based survey of mothers, female adolescents, and healthcare professionals

Vaccine confidence reflects social, individual, and political factors indicating confidence in vaccines and associated health systems. In Japan, the government ceased proactive recommendation of the human papillomavirus (HPV) vaccine in June 2013, only several months after the recommendation had begun. Seven years later, as of October 2020, the suspension persists and vaccine coverage has precipitously declined, resulting in many young women being continually exposed to the risk of preventable HPV-related diseases. Accordingly, understanding stakeholder opinions on HPV vaccination issues is critical for informing strategies to improve HPV vaccine confidence and acceptance. In October 2019, we performed a nationwide, web-based survey of 1646 mothers of HPV-vaccination–eligible girls, 562 female adolescents aged 15–19 years, and 919 healthcare professionals (HCPs) in Japan. This survey captured key elements of vaccine confidence (i.e., importance, effectiveness, and safety of the HPV vaccine), awareness, and the willingness to receive (in HPV-vaccination–eligible girls) or recommend (in HCPs) the HPV vaccine, and the factors responsible for these decisions. HPV vaccine confidence was generally higher among HCPs than among mothers or female adolescents. Nearly half of all stakeholders were neutral regarding their willingness to receive/recommend the HPV vaccine. The seriousness of cervical cancer and the HPV vaccine’s effectiveness or safety were important deciding factors for receiving/recommending the HPV vaccine. Besides these factors, sufficient information and free vaccination were crucial. Our results suggest several factors that could help shape public policy and communication strategies to improve HPV vaccine confidence and acceptance in Japan.

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.

Systematic literature review of cross-protective effect of HPV vaccines based on data from randomized clinical trials and real-world evidence

BACKGROUND

The extent of cross-protection provided by currently licensed bivalent and quadrivalent HPV vaccines versus direct protection against HPV 31-, 33-, 45-, 52-, and 58-related disease is debated. A systematic literature review was conducted to establish the duration and magnitude of cross-protection in interventional and observational studies.

METHODS

PubMed and Embase databases were searched to identify randomized controlled trials (RCT) and observational studies published between 2008 and 2019 reporting on efficacy and effectiveness of HPV vaccines in women against non-vaccine types 31, 33, 45, 52, 58, and 6 and 11 (non-bivalent types). Key outcomes of interest were vaccine efficacy against 6- and 12-month persistent infection or genital lesions, and type-specific genital HPV prevalence or incidence. RCT data were analyzed for the according-to-protocol (bivalent vaccine) or negative-for-14-HPV-types (quadrivalent vaccine) efficacy cohorts.

RESULTS

Data from 23 RCTs and 33 observational studies evaluating cross-protection were extracted. RCTs assessed cross-protection in post-hoc analyses of small size subgroups. Among fully vaccinated, baseline HPV-naïve women, the bivalent vaccine showed statistically significant cross-protective efficacy, although with wide confidence intervals, against 6-month and 12-month persistent cervical infections and CIN2+ only consistently for HPV 31 and 45, with the highest effect observed for HPV 31 (range 64.6% [95% CI: 27.6 to 83.9] to 79.1% [97.7% CI: 27.6 to 95.9] for 6-month persistent infection; maximal follow-up 4.7 years). No cross-protection was shown in extended follow-up. The quadrivalent vaccine efficacy reached statistical significance for HPV 31 (46.2% [15.3-66.4]; follow-up: 3.6 years). Similarly, observational studies found consistently significant effectiveness only against HPV 31 and 45 with both vaccines.

CONCLUSIONS

RCTs and observational studies show that cross-protection is inconsistent across non-vaccine HPV types and is largely driven by HPV 31 and 45. Furthermore, existing data suggest that it wanes over time; its long-term durability has not been established.

Risk factors for HPV infection and high-grade cervical disease in sexually active Japanese women

In Japan, recommendations for HPV vaccines were suspended in 2013 due to unfounded safety fears. Although vaccine opponents claim modifying sexual behavior can prevent cervical cancer, no comprehensive data exist on sexual behavior and the risk of high-grade cervical disease in a Japanese population. This study investigates sexual behavior and the risk of HPV infection and cervical disease in 3968 women aged 20–41 yrs undergoing cervical screening between April 2014 and March 2016. Mean age at first intercourse was 18.4 yrs ± 2.8 and 32% of women reported ≥ 6 lifetime sexual partners. In regression analyses, number of partners was a significant risk factor for HPV infection. However, for high-grade disease (CIN2+), when HPV genotype was adjusted for, number of partners was not statistically significant. The greatest risk factor was an HPV16/18 infection (adjusted odds ratio 113.7, 95% CI: 40.8–316.9). In conclusion, we found that having an HPV16/18 infection and not sexual behavior was the most significant risk factor for high grade cervical disease in young Japanese women. These infections can be prevented by a highly effective vaccine and we recommend that the Japanese government resume proactive recommendations for the HPV vaccine immediately.

Internet Survey of Awareness and Behavior Related to HPV Vaccination in Japan

Recommendations for HPV vaccines were suspended in 2013 due to unfounded safety fears in Japan. We aimed to clarify the differences between vaccinated and unvaccinated females in their awareness, knowledge, and behaviors toward cervical cancer, HPV vaccination and sex. Questionnaires were administered online to women aged 16 to 20. We conducted investigations for the following: awareness, knowledge, and actions for cervical cancer, HPV vaccination, and sexual activity, as well as items related to participants’ social background. The survey in 828 girls revealed three points. The first is that more than half of the surveyed Japanese girls had poor knowledge about cervical cancer screening, HPV, or HPV vaccines. The second is that those in the unvaccinated group had a particularly poor knowledge of the subject and tended to have higher sexual activity. The final is that only 0.5% of the girls experienced changes in awareness about sexual activity after vaccination. In conclusion, this is the first large-scale survey analyzing the association between HPV vaccination and sexual activity in Japanese girls. Not only do unvaccinated girls not benefit from vaccines, but they also tend to engage in high-risk sexual behavior, and thus it is even more important to provide information on the effectiveness of vaccines and the usefulness of cancer screening.

Bivalent Vaccine Effectiveness Against Anal Human Papillomavirus Positivity Among Female Sexually Transmitted Infection Clinic Visitors in the Netherlands

Human papillomavirus (HPV) vaccines are indicated for anal cancer prevention, but evidence for vaccine effectiveness (VE) against anal HPV infections among women is limited. We estimated the VE (≥1 dose) against anal HPV positivity of the bivalent vaccine, whose target types HPV-16/18 are associated with approximately 90% of HPV-related anal cancers. Among 548 female STI clinic visitors 16-24 years old who provided an anal swab sample as part of a repeated cross-sectional survey, VE against HPV-16/18 was 89.9% (95% confidence interval, 63.0%-97.2%). Type-specific VE correlated well with VE against cervicovaginal HPV (Spearman ρ = 0.76), suggesting comparable effectiveness of HPV-16/18 vaccination against genital and anal infections.

Human papillomavirus vaccine to prevent cervical intraepithelial neoplasia in Japan: A nationwide case-control study

Cervical cancer remains among the most common cancers in women worldwide and can be prevented by vaccination. The Ministry of Health, Labour and Welfare of Japan suspended active recommendation of regular human papillomavirus (HPV) vaccines in 2013 because of various symptoms including chronic pain and motor impairment. This nationwide case-control study from April 2013 to March 2017 targeted women aged 20-24 years old at cervical screening. We compared HPV vaccination exposure between those with abnormal and normal cytology. Abnormal cytology was classified based on the results of histological test and we calculated the odds ratio (OR) and 95% confidence interval (CI) of the above endpoints and vaccination exposure using the conditional logistic regression model and estimated vaccine effectiveness using the formula (1 - OR) × 100. A total of 2483 cases and 12 296 controls (one-to-five matching) were eligible in 31 municipalities in Japan. The distribution of histological abnormalities among cases was 797 CIN1 (including dysplasia) (32.1%), 165 CIN2 (6.7%), 44 CIN3 (1.8%), and eight squamous cell carcinoma (SCC) (0.3%). The OR of HPV vaccination compared with no vaccination for abnormal cytology, CIN1+, CIN2+, and CIN3+ versus controls was 0.42 (95% CI, 0.34-0.50), 0.42 (95% CI, 0.31-0.58), 0.25 (95% CI, 0.12-0.54), and 0.19 (95% CI, 0.03-1.15), respectively, equating to a vaccine effectiveness of 58.5%, 57.9%, 74.8%, and 80.9%, respectively. Eight patients had SCC, none was vaccinated. This nationwide case-control study in Japan demonstrated a substantial risk reduction in abnormal cytology and CIN among women who did versus those who did not receive HPV vaccination.

Public preference for COVID-19 vaccines in China: A discrete choice experiment

BACKGROUND

As the coronavirus disease 2019 (COVID-19) pandemic is sweeping across the globe, there is an urgent need to develop effective vaccines as the most powerful strategy to end the pandemic. This study aimed to examine how factors related to vaccine characteristics, their social normative influence and convenience of vaccination can affect the public's preference for the uptake of the COVID-19 vaccine in China.

METHODS

An online discrete choice experiment (DCE) survey was administered to a sample of China's general population. Participants were asked to make a series of hypothetical choices and estimate their preference for different attributes of the vaccine. A mixed logit regression model was used to analyse the DCE data. Willingness to pay for each attribute was also calculated.

RESULTS

Data of 1236 participants who provided valid responses were included in the analysis. There was strong public preference for high effectiveness of the vaccine, followed by long protective duration, very few adverse events and being manufactured overseas. Price was the least important attribute affecting the public preference in selecting the COVID-19 vaccine.

CONCLUSIONS

The strong public preferences detected in this study should be considered when developing COVID-19 vaccination programme in China. The results provide useful information for policymakers to identify the individual and social values for a good vaccination strategy.

PATIENT OR PUBLIC CONTRIBUTION

The design of the experimental choices was fully based on interviews and focus group discussions participated by 26 Chinese people with diverse socio-economic backgrounds. Without their participation, the study would not be possible.

Universal Human Papillomavirus Vaccination and its Impact on the Southern Italian Region

HPV is still the most common sexually transmitted infection, leading to the onset of many disorders while causing an increase in direct and indirect health costs. High Risk (HR) HPV is the primary cause of invasive cervical cancer and contributes significantly to the development of anogenital and oropharyngeal cancers. The introduction of universal HPV vaccination has led to a significant reduction in vaccine-targeted HPV infections, cross-protective genotypes, precancerous lesions and anogenital warts. Despite the several limitations of HPV vaccination programs, including vaccine type specificity, different schedules, target age-groups and poor communication, the impact has become increasingly evident, especially in countries with high vaccine uptake. We carried out a review of the most recent literature to evaluate the effects of HPV vaccination on vaccinetargeted HPV genotypes and to assess the level of cross-protection provided against non-vaccine HPV types. Subsequently, to assess the rates of HPV infection in a southeast Italian region, we performed an epidemiological investigation on the impact of vaccination on genotypes and on the prevalence and distribution of HPV infection during the twelve-year period 2006-2017 in the Local Health Unit (LHU) of Lecce. The vaccination coverage of about 70% among girls in the LHU led to an initial reduction in vaccine-targeted HPV types and cross-protective genotypes. However, the results on this population should be interpreted cautiously because the period since the start of vaccination is too short and the coverage rate is not yet optimal to evaluate the efficacy of vaccination in lowering the prevalence of non-vaccine HR HPV types in the vaccinated cohort and in older subjects. Nevertheless, it is expected that direct effects will increase further and that herd immunity will begin to emerge as vaccination coverage increases.

The study protocol of the evaluation for the preventive efficacy of the HPV vaccine for persistent HPV16/18 infection in Japanese adult women: the HAKUOH study

Background

In general, human papillomavirus (HPV) vaccines have demonstrated efficacy in young women worldwide, but there is limited evidence on the efficacy of the quadrivalent HPV6/11/16/18 vaccine in adult women and no evidence of its effectiveness in Japanese adult women in particular. This study aims to evaluate the efficacy of the quadrivalent HPV6/11/16/18 vaccine for persistent HPV16/18 infection in Japanese women aged 27–45 years.

Methods

This is an interventional, nonrandomized, non-double-blind prospective cohort study designed to compare the rates of persistent HPV16/18 infection between the vaccinated arm and unvaccinated arm. The subjects will consist of all women aged 27–45 years who have normal cytology results confirmed by cervical cancer screening from May 2019 to March 2021. The follow-up time is two years. The subjects will be divided into two groups: the vaccinated group and the unvaccinated group. The study will need to enroll 600 vaccinated participants (experimental arm) and 2200 unvaccinated participants (control arm).

Discussion

The findings of this trial (HAKUOH study) might provide the first local evidence on the subject and be significantly useful not only to medical academia but also to the Japanese Ministry of Health, Labour and Welfare. The findings could contribute to public health improvement by providing local supportive knowledge on the prevention of HPV infection through HPV vaccination in young adult women in Japan, where active recommendations have been suspended for a long time due to adverse effects.

Trial registration

Trial registration number: NCT04022148.

Registration began on December 1, 2019.

Post-hoc analysis of injection-site reactions following vaccination with quadrivalent human papillomavirus vaccine in Japanese female clinical trial participants

AIM

The quadrivalent human papillomavirus (4vHPV) vaccine has demonstrated efficacy and immunogenicity and was generally well tolerated in clinical trials conducted in Japan. We report a detailed safety analysis of injection-site reactions in female Japanese 4vHPV clinical trial participants.

METHODS

This post-hoc analysis included data from 2 double-blind, placebo-controlled phase II clinical trials of a 3-dose (Day 1, Month 2, Month 6) regimen of 4vHPV vaccine in Japanese young women aged 18-26 years (N = 1021; NCT00378560) and girls aged 9-17 years (N = 107; NCT00411749). Injection-site and systemic adverse events (AEs) were monitored using vaccination report cards for 15 days after each vaccine dose; serious AEs were reported throughout the trials. Post-hoc analyses of data from these trials were performed to examine details of injection-site AEs, including day of onset, time from onset to resolution, and maximum intensity.

RESULTS

Injection-site AEs were reported by 85.6% of 4vHPV vaccine recipients and 72.4% of placebo recipients, most commonly erythema, pain, pruritus, and swelling (each >5% of 4vHPV vaccine recipients). The majority of injection-site AEs had an onset within 3 days of vaccination and were mild to moderate in intensity; few 4vHPV vaccine recipients reported severe injection-site AEs (2.0% overall). All injection-site AEs resolved, and most (4vHPV: 87.5%; placebo: 92.7%) resolved within 5 days of onset.

CONCLUSIONS

Most injection-site reactions are mild or moderate in intensity and of short duration. The 3-dose regimen of 4vHPV vaccine is well tolerated in Japanese female clinical trial participants based on this post-hoc analysis. These results will further support safety communication between healthcare providers and vaccine recipients regarding the HPV vaccine.

TRIAL REGISTRATION

Clinicaltrials. gov: NCT00378560 and NCT00411749.

Impact of a High Coverage Vaccination Rate on Human Papillomavirus Infection Prevalence in Young Women: A Cross-sectional Study

OBJECTIVE

The aim of the study was to compare the rate of high-risk human papillomavirus (HR-HPV) genotypes in vaccinated (Gardasil [quadrivalent]) and unvaccinated cohorts of young women.

MATERIALS AND METHODS

This is a retrospective, cross-sectional study, consisting of the comparison of the prevalence of HPV 16, 18, and other HR genotypes in 2183 women younger than 25 years, according to their birth year (born >1994 [mostly vaccinated <13 years]; born 1992-1994 [vaccinated at 17 years]; born <1992 [not vaccinated/vaccinated >17 years]), in a private laboratory.

RESULTS

The rates of HPV 16, 18, 16/18, and others in the cohort born before 1992 (n = 331) were 6.3%, 1.5%, 7.9%, and 31.7%. In those born 1992-1994 (n = 901), the rates were 3.3%, 0.4%, 3.6%, and 32.5%; in the ones born after 1994 (n = 951), the rates were 0.7%, 0.2%, 0.9%, and 33.2%, respectively.There were no changes in the relative risk (RR) of HR-HPV infection by genotypes other than HPV 16/18 in any cohort.The RR was significantly reduced in the cohort born after 1994 for HPV 16 (0.12 [0.050-0.270], p < .0001), HPV 18 (0.14 [0.027-0.714], p = .02), and HPV 16/18 (0.12 [0.057-0.254], p < .0001).In those born 1992-1994, there was a nearly significant reduction in the RR of HPV 18 infection (0.29 [0.079-1.09], p = .07); the reduction was significant for HPV 16 (0.52 [0.305-0.904], p = .02) and HPV 16/18 (0.45 [0.274-0.747], p = .0018).

CONCLUSIONS

Young women vaccinated before 13 years had a nearly 90% risk reduction of HPV 16/18, whereas if vaccinated at 17 years, the decrease was of 50%. There was no impact in the nonvaccine genotypes.Our data highlight the importance of vaccinating at young age and of introducing vaccines covering more HR genotypes.

B. Hanley S, Hara M, Adachi S, Ueda Y, Miyagi E, Ikeda S, Yagi A, Enomoto T. Epidemiologic Profile of Type-Specific Human Papillomavirus Infection after Initiation of HPV Vaccination

Organized human papillomavirus vaccination (OHPV) in Japan was introduced in 2010 for girls aged 12–16 years who were born in 1994 or later. The rate of OHPV coverage was 70–80%. However, after suspension of the government vaccination recommendation, the coverage dramatically decreased. We aim to investigate the change in prevalence of HPV infection after the initiation of HPV vaccination. We recruited females aged 20–21 years attending public cervical cancer screening from 2014 to 2017 fiscal years (April 2014 to March 2018). Residual Pap test specimens were collected for HPV testing. We compared the prevalence of HPV type-specific infection between women registered in 2014 (born in 1993–1994, including the pre-OHPV generation) and registered in 2015–2017 (born in 1994–1997, the OHPV generation). We collected 2379 specimens. The vaccination coverage figures were 30.7%, 86.6%, 88.4% and 93.7% (p < 0.01) from 2014 to 2017, respectively. The prevalence of HPV16/18 infection significantly decreased from 1.3% in 2014 to 0% in 2017 (p = 0.02). The three most prevalent types were HPV52, 16 and 56 in 2014, and HPV52, 58 and 56 in 2015–2017, respectively. HPV16 and 33 infection rates decreased. On the other hand, the HPV58 infection rate was obviously increased after OHPV from 0.3% to 2.1%. Our study demonstrates that the prevalence of HPV16/18 infection dramatically decreased and the profile of type-specific HPV infection was changed after OHPV.

Long-term follow-up of human papillomavirus type replacement among young pregnant Finnish females before and after a community-randomised HPV vaccination trial with moderate coverage

Large scale human papillomavirus (HPV) vaccination against the most oncogenic high-risk human papillomavirus (HPV) types 16/18 is rapidly reducing their incidence. However, attempts at assessing if this leads to an increase of nonvaccine targeted HPV types have been hampered by several limitations, such as the inability to differentiate secular trends. We performed a population-based serological survey of unvaccinated young women over 12 years. The women were under 23-years-old, residents from 33 communities which participated in a community-randomised trial (CRT) with approximately 50% vaccination coverage. Serum samples were retrieved pre-CRT and post-CRT implementation. Seropositivity to 17 HPV types was assessed. HPV seroprevalence ratios (PR) comparing the postvaccination to prevaccination era were estimated by trial arm. This was also assessed among the sexual risk-taking core group, where type replacement may occur more rapidly. In total, 8022 serum samples from the population-based Finnish Maternity Cohort were retrieved. HPV types 16/18 showed decreased seroprevalence among the unvaccinated in communities only after gender-neutral vaccination (PR_16/18A = 0.8, 95% CI 0.7-0.9). HPV6/11 and HPV73 were decreased after gender-neutral vaccination (PR_6/11A = 0.8, 95% CI 0.7-0.9, PR_73A = 0.7, 95% CI 0.6-0.9, respectively) and girls-only vaccination (PR_6/11B = 0.8, 95% CI 0.7-0.9, PR_73B = 0.9, 95% CI 0.8-1.0). HPV68 alone was increased but only after girls-only vaccination (PR_68B = 1.3, 95% CI 1.0-1.7, PR_core68B = 2.8, 95% CI 1.2-6.3). A large-scale, long-term follow-up found no type replacement in the communities with the strongest reduction of vaccine HPV types. Limited evidence for an increase in HPV68 was restricted to girls-only vaccinated communities and may have been due to secular trends (ClinicalTrials.gov number: NCT00534638).

Japan's Ongoing Crisis on HPV Vaccination

The Japanese government suspended proactive recommendations for the HPV vaccine in June 2013. The suspension is now in its seventh year, despite all the data pointing to the safety of the HPV vaccine. We reported a high vaccine effectiveness in the group of women vaccinated before their first intercourse (93.9%). The prevalence of cross-protected types of HPV 31/45/52 was also lower in the vaccinated group, and the vaccine effectiveness was 67.7%. Furthermore, prevalence of HPV16, 31 and 52 infection rates in the vaccinated group were obviously lower than that in the unvaccinated group, and no one had HPV18 or 45 infection in the vaccinated group. The addition of a cross-protective effect toward HPV types 31/45/52 to HPV types 16/18, which is the direct target of the bivalent HPV vaccine, may possibly prevent around 82% of invasive cervical cancer cases in Japan. With regard to the preventive effect of histological abnormalities, we also reported significant reduction in incidence of cervical intraepithelial neoplasia (CIN)3 or worse. Thus, the efficacy of the vaccine has been demonstrated for precancerous disease, and the diverse symptoms after HPV vaccination are likely functional somatic. For the future of Japanese girls, there is a need to resume the proactive recommendation of HPV vaccination and for immediate action to be taken by the Japanese government.

The effects of health education on health science teachers' intention to recommend adolescent HPV vaccine for female students in Japan

The Japanese government suspended proactive recommendation of human papillomavirus (HPV) vaccination due to several reports of adverse events related to it in 2013. After that, the immunization rate of HPV vaccine quickly declined in Japan. Health science teachers (HSTs) are qualified and licensed teachers in charge of health care and health education for students in Japanese schools. HSTs have not recommended HPV vaccination to female students, since active governmental recommendation for HPV vaccination was halted for 5 y. We conducted a primary survey targeting HSTs (N = 39) and university students taking the HST training course (N = 123). In each group, awareness regarding HPV vaccine and disease burden was evaluated and factors related to and barriers to HPV vaccine recommendation were identified. The primary survey found that many HSTs and university students recognized their insufficient knowledge regarding the HPV vaccine. Based on the primary survey's results, infectious disease specialists, collaborating with Japanese HSTs, developed educational slide sets on HPV vaccine. A secondary survey was conducted before and after the lecture with HSTs (N = 162), where we evaluated their intelligibility and intention to recommend HPV vaccination for female students. In the post-lecture, secondary survey, the number of HSTs who recommended the HPV vaccine to their students had statistically increased from 76 before the lecture, to 103 (p < .05). An educational lecture using appropriate materials improved HSTs' vaccine confidence and intention to recommend the HPV vaccine to their students, verifying the study's hypothesis.

Peak neutralizing and cross-neutralizing antibody levels to human papillomavirus types 6/16/18/31/33/45/52/58 induced by bivalent and quadrivalent HPV vaccines

We performed an independent comparison of neutralizing and cross-neutralizing antibody (ab) levels seven months after initiation of three-dose, six-month vaccination schedules with the bivalent and quadrivalent human papillomavirus (HPV) vaccines in adolescent Finnish and Indian females, respectively. We used a semi-automated Pseudovirion-Based Neutralization Assay and observed significantly higher HPV16/18 peak ab-levels in bivalent as compared to quadrivalent vaccine recipients. Bivalent vaccine induced cross-neutralizing HPV31/33/45/52/58 antibodies significantly more frequently and to higher levels than the quadrivalent vaccine. The correlation of bivalent vaccine-induced HPV45 ab-levels with HPV16/18 ab-levels was stronger than that of corresponding quadrivalent vaccine-induced ab-levels, suggesting a qualitatively different cross-reactive response. Our findings on the comparison of the immunogenicity of two HPV vaccine tested in two different populations indicate that further head-to-head studies are warranted.

Reduction in HPV16/18 prevalence among young women with high-grade cervical lesions following the Japanese HPV vaccination program

The Japanese government began a human papillomavirus (HPV) vaccination program for girls aged 12‐16 years in 2010 but withdrew its recommendation in 2013 because of potential adverse effects, leading to drastically reduced vaccination uptake. To evaluate population‐level effects of HPV vaccination, women younger than 40 years of age newly diagnosed with cervical intraepithelial neoplasia grade 1‐3 (CIN1‐3), adenocarcinoma in situ (AIS), or invasive cervical cancer (ICC) have been registered at 21 participating institutes each year since 2012. A total of 7709 women were registered during 2012‐2017, of which 5045 were HPV genotyped. Declining trends in prevalence of vaccine types HPV16 and HPV18 during a 6‐year period were observed in CIN1 (50.0% to 0.0%, P_trend < .0001) and CIN2‐3/AIS (83.3% to 45.0%, P_trend = .07) only among women younger than 25 years of age. Overall, HPV vaccination reduced the proportion of HPV16/18‐attributable CIN2‐3/AIS from 47.7% to 33.0% (P = .003): from 43.5% to 12.5% as routine vaccination (P = .08) and from 47.8% to 36.7% as catch‐up vaccination (P = .04). The HPV16/18 prevalence in CIN2‐3/AIS cases was significantly reduced among female individuals who received their first vaccination at age 20 years or younger (P = .02). We could not evaluate vaccination effects on ICC owing to low incidence of ICC among women aged less than 25 years. We found HPV vaccination to be effective in protecting against HPV16/18‐positive CIN/AIS in Japan; however, our data did not support catch‐up vaccination for women older than 20 years. Older adolescents who skipped routine vaccination due to the government’s suspension of its vaccine recommendation could benefit from receiving catch‐up vaccination before age 20 years.

Priming effect of bivalent and quadrivalent vaccine for HPV 31/33/45/52: an exploratory analysis from two clinical trials

The main objective of this post hoc analysis is to compare the magnitude of the immune response to HPV31/33/45/52 and 58 after a dose of 9vHPV vaccine given to naïve (previously unvaccinated) subjects and subjects previously vaccinated with a dose of 2vHPV or 4vHPV vaccine. Results from two clinical trials conducted in the same region, in comparable populations and by the same research team were included in this analysis. In study A, a dose of 9vHPV was administered 6 months after a single dose of 2vHPV as well as to naïve subjects. In study B, a dose of 9vHPV was administered 36-96 months (mean 65 months) after a single dose of 4vHPV. Blood samples were collected just before and one month post-9vHPV vaccine administration. For both studies, antibody responses were measured using the same 9-plex virus-like particle based IgG ELISA (M9ELISA). One month after 9vHPV dose administration, all subjects were seropositive to HPV 31/33/45/52 and 58. Subjects who had previously received 2vHPV or 4vHPV had significantly higher (1.8-8.0-fold) GMTs than naive subjects for HPV31/33/45/52 types but not for HPV58. GMTs to HPV31/33/45/52 and 58 were not significantly different between subjects who received a 2vHPV or 4vHPV dose prior to 9vHPV. The strong anamnestic response to one dose of 9vHPV given as late as 3-8 years after a single dose of 2vHPV or 4vHPV vaccine indicates these vaccines induced priming to types only included in the 9vHPV vaccine.

Asian Society of Gynecologic Oncology International Workshop 2018

The Asian Society of Gynecologic Oncology International Workshop 2018 on gynecologic oncology was held in the Ajou University Hospital, Suwon, Korea on the 24th to 25th August 2018. The workshop was an opportunity for Asian doctors to discuss the latest findings of gynecologic cancer, including cervical, ovarian, and endometrial cancers, as well as the future of fertility-sparing treatments, minimally invasive/radical/debulking surgery, radiotherapy, chemotherapy, targeted therapy, and immunotherapy. Clinical guidelines and position statement of Asian countries were presented by experts. Asian clinical trials for gynecologic cancers were reviewed and experts emphasized the point that original Asian study is beneficial for Asian patients. In Junior session, young gynecologic oncologists presented their latest research on gynecologic cancers.