Model for assessing human papillomavirus vaccination strategies.
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ABSTRACT:
SUBMITTER: Elbasha EH
PROVIDER: S-EPMC2725801 | biostudies-literature | 2007 Jan
REPOSITORIES: biostudies-literature
Publications
Model for assessing human papillomavirus vaccination strategies.
Elbasha Elamin H EH Dasbach Erik J EJ Insinga Ralph P RP
Emerging infectious diseases 20070101 1
We present a transmission dynamic model that can assess the epidemiologic consequences and cost-effectiveness of alternative strategies of administering a prophylactic quadrivalent (types 6/11/16/18) human papillomavirus (HPV) vaccine in a setting of organized cervical cancer screening in the United States. Compared with current practice, vaccinating girls before the age of 12 years would reduce the incidence of genital warts (83%) and cervical cancer (78%) due to HPV 6/11/16/18. The incremental ...[more]
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Project description:ImportanceCervical cancer screening is a lifesaving intervention, with an array of approaches, including liquid-based cytology (LBC), molecular testing for human papillomavirus (HPV) infection, and combinations via parallel cotesting or sequential triage. Maximizing screening efficacy while minimizing overtreatment is vital, especially when considering how the HPV vaccine will affect the interpretation of results.ObjectivesTo estimate the likely outcomes of different screening modalities and to model how the increasing uptake of the HPV vaccine could affect the interpretation of screening results.Design, setting, and participantsThis decision analytic model established a simple Markov model to compare the outcomes of different cervical cancer screening modalities on a simulated population of women (aged ≥25 years), considering different levels of HPV vaccination.Main outcomes and measuresThe number of cases of cervical intraepithelial neoplasia (CIN) grade 2 and 3 detected and missed, the number of false positives, and the number of tests required to achieve a given level of accuracy. Positive and negative predictive values of different modalities were simulated under varying levels of HPV vaccination and therefore HPV prevalence.ResultsIn a simulated population of 1000 women aged 25 years and older with an HPV prevalence of 2%, HPV-based modalities outperformed LBC-based approaches, detecting 19% more true positives (HPV test sensitivity, 89.9% [95% CI, 88.6%-91.1%]; LBC test sensitivity, 75.5% [95% CI, 66.6%-82.7%]). While cotesting markedly reduced missed cases, detecting 29% more true positives than LBC alone (19.5 [95% CI, 19.3-19.7] per 1000 women screened vs 15.1 [95% CI, 13.3-16.5] per 1000 women screened), it unacceptably increased excess colposcopy referral by 94% (184.4 [95% CI, 181.8-188.0] false positives per 1000 women screened vs 95.1 [95% CI, 93.1-97.0] false positives per 1000 women screened). By contrast, triage testing with reflex screening substantially reduced false positives by a factor of approximately 10 (eg, HPV with LBC triage, 9.6 [95% CI, 9.3-10.0] per 1000 women screened). Over a lifetime of screening, reflex approaches with appropriate test intervals maximized therapeutic efficacy; as HPV vaccination rates increased, HPV-based screening approaches resulted in fewer unnecessary colposcopies than LBC approaches (HPV testing, 80% vaccine coverage: 44.1 [95% CI, 40-45.9] excess colposcopies; LBC testing, 80% vaccine coverage: 96.9 [95% CI, 96.8-97.0] excess colposcopies).Conclusions and relevanceIn this decision analytic model, the effectiveness of cervical cancer screening was dependent on the prevalence of cervical dysplasia and/or HPV infection or vaccination in a population as well as the sensitivity and specificity of various modalities. Although screening is lifesaving, overtesting or modalities inappropriate to the target population may cause significant harm, including overtreatment.
| S-EPMC8246311 | biostudies-literature
Project description:IntroductionWe 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.MethodsGirls 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.ResultsOf 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.ConclusionsThis 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.
| S-EPMC8559511 | biostudies-literature
Project description:BACKGROUND:We compared vaccine coverage achieved by 2 different delivery strategies for the quadrivalent human papillomavirus (HPV) vaccine in Tanzanian schoolgirls. METHODS:In a cluster-randomized trial of HPV vaccination conducted in Tanzania, 134 primary schools were randomly assigned to class-based (girls enrolled in primary school grade [class] 6) or age-based (girls born in 1998; 67 schools per arm) vaccine delivery. The primary outcome was coverage by dose. RESULTS:There were 3352 and 2180 eligible girls in schools randomized to class-based and age-based delivery, respectively. HPV vaccine coverage was 84.7% for dose 1, 81.4% for dose 2, and 76.1% for dose 3. For each dose, coverage was higher in class-based schools than in age-based schools (dose 1: 86.4% vs 82.0% [P = .30]; dose 2: 83.8% vs 77.8% [P = .05]; and dose 3: 78.7% vs 72.1% [P = .04]). Vaccine-related adverse events were rare. Reasons for not vaccinating included absenteeism (6.3%) and parent refusal (6.7%). School absenteeism rates prior to vaccination ranged from 8.1% to 23.5%. CONCLUSIONS:HPV vaccine can be delivered with high coverage in schools in sub-Saharan Africa. Compared with age-based vaccination, class-based vaccination located more eligible pupils and achieved higher coverage. HPV vaccination did not increase absenteeism rates in selected schools. Innovative strategies will be needed to reach out-of-school girls. CLINICAL TRIALS REGISTRATION:NCT01173900.
| S-EPMC3414230 | biostudies-literature
Project description:BackgroundIn 2007, Australia implemented the National human papillomavirus (HPV) Vaccination Program, which provides quadrivalent HPV vaccine free to all women aged 12-26 years. Following notification of 7 presumptive cases of anaphylaxis in the state of New South Wales, Australia, we verified cases and compared the incidence of anaphylaxis following HPV vaccination to other vaccines in comparable settings.MethodsWe contacted all patients with suspected anaphylaxis and obtained detailed histories from telephone interviews and a review of medical records. A multidisciplinary team determined whether each suspected case met the standardized Brighton definition. Some participants also received skin-prick allergy testing for common antigens and components of the HPV vaccine.ResultsOf 12 suspected cases, 8 were classified as anaphylaxis. Of these, 4 participants had negative skin-prick test results for intradermal Gardasil. From the 269 680 HPV vaccine doses administered in schools, 7 cases of anaphylaxis were identified, which represents an incidence rate of 2.6 per 100 000 doses (95% CI 1.0-5.3 per 100 000). In comparison, the rate of identified anaphylaxis was 0.1 per 100 000 doses (95% CI 0.003-0.7) for conjugated meningococcal C vaccination in a 2003 school-based program.InterpretationBased on the number of confirmed cases, the estimated rate of anaphylaxis following quadrivalent HPV vaccine was significantly higher than identified in comparable school-based delivery of other vaccines. However, overall rates were very low and managed appropriately with no serious sequelae.
| S-EPMC2527382 | biostudies-literature
Project description:BackgroundVaccination against human papillomavirus (HPV), predominantly targeting young females, has been introduced in many countries. Decisions to implement programs, which have involved substantial investment by governments, have in part been based on findings from cost-effectiveness models. Now that vaccination programs have been in place for some years, it is becoming possible to observe their effects, and compare these with model effectiveness predictions made previously.FindingsAustralia introduced a publicly-funded HPV vaccination program in 2007. Recently reported Australian data from a repeat cross-sectional survey showed a substantial (77%) fall in HPV16 prevalence in women aged 18-24 years in 2010-2011, compared to pre-vaccination levels. We have previously published model predictions for the population-wide reduction in incident HPV16 infections post-vaccination in Australia. We compared prior predictions from the same model (including the same assumed uptake rates) for the reduction in HPV16 prevalence in women aged 18-24 years by the end of 2010 with the observed data. Based on modelled vaccine uptake which is consistent with recent data on three-dose uptake (78% at 12-13 years; lower uptake in older catch-up age cohorts), we had predicted a 70% reduction in prevalence in 18-24 year old females by the end of 2010. Based on modelled vaccine uptake consistent with recent national data for two-dose coverage and similar to that reported by women in the cross-sectional study, we had predicted a 79% reduction.ConclusionsA close correspondence was observed between the prior model predictions and the recently reported findings on the rapid drop in HPV prevalence in Australia. Because broadly similar effectiveness predictions have been reported from other models used for cost-effectiveness predictions, this provides reassurance that the substantial public investment in HPV vaccination has been grounded in valid estimates of the effects of vaccination.
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Project description:Human papillomavirus (HPV) is a prevalent cause of mucosal and cutaneous infections and underlying conditions ranging from benign warts to anogenital and oropharyngeal cancers affecting both males and females, notably cervical cancer. Cervical cancer is the fourth leading cause of cancer deaths among women globally and is the most impactful in low- and middle-income countries (LMICs), where the costs of screening and licensed L1-based HPV vaccines pose significant barriers to comprehensive administration. Additionally, the licensed L1-based HPV vaccines fail to protect against all oncogenic HPV types. This study generated three independent lots of an L2-based target antigen (LBTA), which was engineered from conserved linear L2-protective epitopes (aa11-88) from five human alphapapillomavirus genotypes in E. coli under cGMP conditions and adjuvanted with aluminum phosphate. Vaccination of rabbits with LBTA generated high neutralizing antibody titers against all 17 HPV types tested, surpassing the nine types covered by Gardasil®9. Passive transfer of naïve mice with LBTA antiserum revealed its capacity to confer protection against vaginal challenge with all 17 αHPV types tested. LBTA shows stability at room temperature over >1 month. Standard in vitro and in vivo toxicology studies suggest a promising safety profile. These findings suggest LBTA's promise as a next-generation vaccine with comprehensive coverage aimed at reducing the economic and healthcare burden of cervical and other HPV+ cancers in LMICs, and it has received regulatory approval for a first-in-human clinical study (NCT05672966).
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Project description:Recent findings suggest that the rate of certain cancers can be reduced by increasing human papillomavirus (HPV) vaccination coverage, resulting in considerable research interest on the antecedents of HPV vaccine receipt to identify avenues to promote vaccination. The current article continues this stream of research by (1) studying the three HPV vaccination outcomes of willingness, receipt, and word-of-mouth, (2) investigating the antecedent effects of sociodemographic characteristics, health insurance status, provider conversation, and political orientation, and (3) testing the mediating role of vaccine hesitancy dimensions using a recently developed conceptualization. We achieve these goals by conducting a cross-sectional study with 404 participants (Agemean = 37.64; AgeSD = 14.91; 57% female; 72% white; 100% located in U.S.). Our results show that provider conversations and political orientation had the most consistent and strong effects of the personal characteristics, whereas perceptions that vaccines pose health risks and perceptions that vaccines are not needed for healthy individuals produced the most consistent and strong effects of the vaccine hesitancy dimensions. Other personal characteristics and vaccine hesitancy dimensions also produced intermittent significant effects, including age, education, and race. Together, these results support that personal characteristics and vaccine hesitancy dimensions relate to a broader range of outcomes associated with HPV vaccination than previously known, and these results also support that the recently developed conceptualization of vaccine hesitancy is apt for understanding HPV vaccine perceptions. Our discussion concludes with highlighting avenues for future research and practice that can leverage our discovered relations to improve HPV vaccination outcomes.
| S-EPMC10903565 | biostudies-literature
Project description:High-risk types of human papillomavirus (HPV) cause over 500,000 cervical, anogenital and oropharyngeal cancer cases per year. The transforming potential of HPVs is mediated by viral oncoproteins. These are essential for the induction and maintenance of the malignant phenotype. Thus, HPV-mediated malignancies pose the unique opportunity in cancer vaccination to target immunologically foreign epitopes. Therapeutic HPV vaccination is therefore an ideal scenario for proof-of-concept studies of cancer immunotherapy. This is reflected by the fact that a multitude of approaches has been utilized in therapeutic HPV vaccination design: protein and peptide vaccination, DNA vaccination, nanoparticle- and cell-based vaccines, and live viral and bacterial vectors. This review provides a comprehensive overview of completed and ongoing clinical trials in therapeutic HPV vaccination (summarized in tables), and also highlights selected promising preclinical studies. Special emphasis is given to adjuvant science and the potential impact of novel developments in vaccinology research, such as combination therapies to overcome tumor immune suppression, the use of novel materials and mouse models, as well as systems vaccinology and immunogenetics approaches.
| S-EPMC4494257 | biostudies-literature
Project description:The vaccines are considered to be important for the prevention and control of coronavirus disease 2019 (COVID-19). However, considering the limited vaccine supply within an extended period of time in many countries where COVID-19 vaccine booster shot are taken and new vaccines are developed to suppress the mutation of virus, designing an effective vaccination strategy is extremely important to reduce the number of deaths and infections. Then, the simulations were implemented to study the relative reduction in morbidity and mortality of vaccine allocation strategies by using the proposed model and actual South Africa's epidemiological data. Our results indicated that in light of South Africa's demographics, vaccinating older age groups (>60 years) largely reduced the cumulative deaths and the "0-20 first" strategy was the most effective way to reduce confirmed cases. In addition, "21-30 first" and "31-40 first" strategies have also had a positive effect. Partial vaccination resulted in lower numbers of infections and deaths under different control measures compared with full vaccination in low-income countries. In addition, we analyzed the sensitivity of daily testing volume and infection rate, which are critical to optimize vaccine allocation. However, comprehensive reduction in infections was mainly affected by the vaccine proportion of the target age group. An increase in the proportion of vaccines given priority to "0-20" groups always had a favorable effect, and the prioritizing vaccine allocation among the "60+" age group with 60% of the total amount of vaccine consistently resulted in the greatest reduction in deaths. Meanwhile, we observed a significant distinction in the effect of COVID-19 vaccine allocation policies under varying priority strategies on relative reductions in the effective reproduction number. Our results could help evaluate to control measures performance and the improvement of vaccine allocation strategy for COVID-19 epidemic.
| S-EPMC9240634 | biostudies-literature
Project description:The epidemiological and clinical aspects of Human Papillomavirus (HPV) infection in women have been extensively studied. However, there is a lack of information regarding HPV characteristics in males. In this study, we conducted a retrospective and observational study of 3737 consecutive male individuals attending outpatient clinics of Guangdong Women and Children Hospital from 2012 to 2023 in Guangzhou, South China, to determine the age- and genotype-specific prevalence of HPV in men. The results showed the overall prevalence of HPV among men was 42.15% (1575/3737), with variations ranging from 29.55% to 81.31% across distinct diagnostic populations. Low-risk HPV6 (15.47%), HPV11 (8.94%), and high-risk HPV52 (5.51%) were the most common types. The annual HPV prevalence decreased significantly (Z = -3.882, p < .001), ranging from 31.44% to 52.90%. 28.77% (1075/3737) of men manifested infection with a singular HPV type, predominantly identified as a low-risk type. The age-specific distribution of HPV infections revealed distinctive peaks in the < 25 y age group (47.60%, 208/437) and the 40-44 y age group (44.51%, 154/346). Notably, the positive rate of Chlamydia trachomatis was significantly higher among HPV-positive individuals in comparison to HPV-negatives (16.14% vs. 11.25%, p < .05). Our findings reveal a substantial prevalence of HPV infection among outpatient men in Guangzhou, South China. It is recommended to consider the inclusion of HPV vaccination for adolescent males in national immunization schedules, once an adequate supply of vaccines is accessible.
| S-EPMC10993917 | biostudies-literature