Human papillomavirus vaccine effectiveness by number of doses: Updated systematic review of data from national immunization programs

Cost-Effectiveness of Human Papillomavirus Vaccination in the UK: Two Versus Single-Dose of Nonavalent HPV Vaccination

INTRODUCTION

The UK implemented a single-dose HPV vaccination policy in September 2023, aiming for sustained protection, better vaccine coverage, and reduced healthcare costs. This research assesses the cost-effectiveness of both one-dose and two-dose schedules from a healthcare perspective.

METHODS

Using an age-structured dynamic model, the study analyzed long-term health and economic outcomes of these two different vaccination approaches. It focused on the effects of vaccinating 12- to 13-year-olds with the 9-valent HPV vaccine in either single-dose or two-dose regimens from 2023 to 2093. The analysis, conducted in 2023-2024, explored different immunity durations (10, 30 years, or lifetime) and efficacy levels for the single-dose strategy.

RESULTS

The study indicated that in the UK, vaccinating 12- to 13-year-olds with a two-dose regimen is not considered cost-effective compared to the single-dose option, assumed to be 90% as effective for 10 years. The incremental cost-effectiveness ratios for two doses ranged from £230,903 to £1,082,916 per quality-adjusted life year (QALY), significantly exceeding the UK's £20,000/QALY willingness-to-pay threshold. Over 70 years, a switch from a two-dose to a single-dose vaccination schedule could potentially lead to savings of over £1,073 million in the healthcare system. Furthermore, the single-dose regimen was cost-effective compared to no vaccination, with an incremental cost-effectiveness ratio below £2,040/QALY.

CONCLUSIONS

The study affirms the cost-effectiveness of the UK's single-dose HPV vaccine, in sync with its September 2023 policy shift. The shift not only provides financial benefits but also simplifies vaccine administration, strategically reducing HPV's epidemiological and economic impacts.

Cervical Cancer: Precursors and Prevention

Cervical cancer, caused due to oncogenic types of human papillomavirus (HPV), is a leading preventable cause of cancer morbidity and mortality globally. Chronic, persistent HPV infection-induced cervical precursor lesions, if left undetected and untreated, can progress to invasive cancer. Cervical cancer screening approaches have evolved from cytology (Papanicolaou test) to highly sensitive HPV-based molecular methods and personalized, risk-stratified, management guidelines. Innovations like self-collection of samples to increase screening access, innovative triage methods to optimize management of screen positives, and scalable and efficacious precancer treatment approaches will be key to further enhance the utility of prevention interventions.

Efficacy and immunogenicity of a single dose of human papillomavirus vaccine compared to multidose vaccination regimens or no vaccination: An updated systematic review of evidence from clinical trials

Objectives

This study systematically reviewed the published literature from clinical trials on the efficacy and immunogenicity of single-dose HPV vaccination compared to multidose schedules or no HPV vaccination.

Methods

Four databases were searched for relevant articles published from Jan-1999 to Feb-2023. Articles were assessed for eligibility for inclusion using pre-defined criteria. Relevant data were extracted from eligible articles and a descriptive quality assessment was performed for each study. A narrative data synthesis was conducted, examining HPV infection, other clinical outcomes and immunogenicity responses by dose schedule.

Results

Fifteen articles reporting data from six studies (all in healthy young females) were included. One article was included from each of three studies that prospectively randomised participants to receive a single HPV vaccine dose versus one or more comparator schedule(s). The other 12 articles reported data from three studies that randomised participants to receive multidose HPV vaccine (or control vaccine) schedules; in those studies, some participants failed to complete their allocated schedule, and evaluations were conducted to compare participants who actually received one, two or three doses. Across all efficacy studies, the incidence or prevalence of HPV16/18 infection was very low among HPV-vaccinated participants, regardless of the number of doses received; with no evidence for a difference between dose groups. In immunogenicity studies, HPV16/18 antibody seropositivity rates were high among all HPV-vaccinated participants. Antibody levels were significantly lower with one dose compared to two or three doses, but levels with one dose were stable and sustained to 11 years post-vaccination.

Conclusions

Results from this review support recent World Health Organization recommendations allowing either one- or two-dose HPV vaccination in healthy young females. Longer-term efficacy and immunogenicity data from ongoing studies are awaited. Randomised trials of single-dose HPV-vaccination are urgently needed in other populations, e.g. boys, older females and people with HIV.

Comparing one dose of HPV vaccine in girls aged 9-14 years in Tanzania (DoRIS) with one dose in young women aged 15-20 years in Kenya (KEN SHE): an immunobridging analysis of randomised controlled trials

BACKGROUND

The first randomised controlled trial of single-dose human papillomavirus (HPV) vaccine efficacy, the Kenya single-dose HPV-vaccine efficacy (KEN SHE) trial, showed greater than 97% efficacy against persistent HPV16 and HPV18 infection at 36 months among women in Kenya. We compared antibody responses after one dose of HPV vaccine in the Dose Reduction Immunobridging and Safety Study (DoRIS), the first randomised trial of the single- dose regimen in girls aged 9-14 years, the target age range for vaccination, with those after one dose of the same vaccine in KEN SHE.

METHODS

In the DoRIS trial, 930 girls aged 9-14 years in Tanzania were randomly assigned to one, two, or three doses of the 2-valent vaccine (Cervarix) or the 9-valent vaccine (Gardasil-9). The proportion seroconverting and geometric mean concentrations (GMCs) at month 24 after one dose were compared with those in women aged 15-20 years who were randomly assigned to one dose of the same vaccines at the same timepoint in KEN SHE. Batched samples were tested together by virus-like particle ELISA for HPV16 and HPV18 IgG antibodies. Non-inferiority of GMC ratios (DoRIS trial:KEN SHE) was predefined as a lower bound of the 95% CI less than 0·50.

FINDINGS

Month 24 HPV16 and HPV18 antibody GMCs in DoRIS were similar or higher than those in KEN SHE. 2-valent GMC ratios were 0·90 (95% CI 0·72-1·14) for HPV16 and 1·02 (0·78-1·33) for HPV18. 9-valent GMC ratios were 1·44 (95% CI 1·14-1·82) and 1·47 (1·13-1·90), respectively. Non-inferiority of antibody GMCs and seropositivity was met for HPV16 and HPV18 for both vaccines.

INTERPRETATION

HPV16 and HPV18 immune responses in young girls 24 months after a single dose of 2-valent or 9-valent HPV vaccine were comparable to those in young women who were randomly assigned to a single dose of the same vaccines and in whom efficacy had been shown. A single dose of HPV vaccine, when given to girls in the target age range for vaccination, induces immune responses that could be effective against persistent HPV16 and HPV18 infection at least two years after vaccination.

FUNDING

The UK Department of Health and Social Care, the Foreign, Commonwealth, & Development Office, the Global Challenges Research Fund, the UK Medical Research Council and Wellcome Trust Joint Global Health Trials scheme, the Bill and Melinda Gates Foundation, the US National Cancer Institute; the US National Institutes of Health, and the Francis and Dorothea Reed Endowed Chair in Infectious Diseases.

TRANSLATION

For the KiSwahili translation of the abstract see Supplementary Materials section.

Vaccination Effectiveness against Human Papillomavirus in Kazakhstan

OBJECTIVE

The purpose was to determine the effectiveness of human papillomavirus immunization and its impact on cervical cancer development in Kazakhstan.

METHODS

The current research is a case-control study with two groups: a main group and a control group. A total of 725 subjects participated in the research.

RESULTS

The association between vaccination and cervical cancer development was calculated both for the two groups as a whole and for individual patients, who were selected based on criteria of residence, presence of immunodeficiency or chronic cardiac or renal pathology, as well as analysis of age at which the vaccine dose was received. There was a statistically significant association between the absence of the human papillomavirus vaccine and the risk of cervical cancer in all groups. When considering the entire cohort, the chance of finding a risk factor (lack of vaccination) was almost 7 times higher in the main group than in the control group. Thus, an association between vaccination and cervical cancer risk was found in each of the pairs of subjects.

CONCLUSION

The effectiveness of vaccination in preventing cervical cancer was not observed in patients who were vaccinated after 18 years of age, while most patients in the control group were vaccinated in their teens. The practical significance of the research is not only to further study the problem of human papillomavirus (HPV) vaccination in Kazakhstan but also to popularize HPV immunization to prevent cervical cancer (CC).

Virus-like particle vaccine displaying an external, membrane adjacent MUC16 epitope elicits ovarian cancer-reactive antibodies

BACKGROUND

MUC16 is a heavily glycosylated cell surface mucin cleaved in the tumor microenvironment to shed CA125. CA125 is a serum biomarker expressed by > 95% of non-mucinous advanced stage epithelial ovarian cancers. MUC16/CA125 contributes to the evasion of anti-tumor immunity, peritoneal spread and promotes carcinogenesis; consequently, it has been targeted with antibody-based passive and active immunotherapy. However, vaccination against this self-antigen likely requires breaking B cell tolerance and may trigger autoimmune disease. Display of self-antigens on virus-like particles (VLPs), including those produced with human papillomavirus (HPV) L1, can efficiently break B cell tolerance.

RESULTS

A 20 aa juxta-membrane peptide of the murine MUC16 (mMUC16) or human MUC16 (hMUC16) ectodomain was displayed either via genetic insertion into an immunodominant loop of HPV16 L1-VLPs between residues 136/137, or by chemical coupling using malemide to cysteine sulfhydryl groups on their surface. Female mice were vaccinated intramuscularly three times with either DNA expressing L1-MUC16 fusions via electroporation, or with alum-formulated VLP chemically-coupled to MUC16 peptides. Both regimens were well tolerated, and elicited MUC16-specific serum IgG, although titers were higher in mice vaccinated with MUC16-coupled VLP on alum as compared to L1-MUC16 DNA vaccination. Antibody responses to mMUC16-targeted vaccination cross-reacted with hMUC16 peptide, and vice versa; both were reactive with the surface of CA125+ OVCAR3 cells, but not SKOV3 that lack detectable CA125 expression. Interestingly, vaccination of mice with mMUC16 peptide mixed with VLP and alum elicited mMUC16-specific IgG, implying VLPs provide robust T help and that coupling may not be required to break tolerance to this epitope.

CONCLUSION

Vaccination with VLP displaying the 20 aa juxta-membrane MUC16 ectodomain, which includes the membrane proximal cleavage site, is likely to be well tolerated and induce IgG targeting ovarian cancer cells, even after CA125 is shed.

Durability of single-dose HPV vaccination in young Kenyan women: randomized controlled trial 3-year results

Cervical cancer burden is high where prophylactic vaccination and screening coverage are low. We demonstrated in a multicenter randomized, double-blind, controlled trial that single-dose human papillomavirus (HPV) vaccination had high vaccine efficacy (VE) against persistent infection at 18 months in Kenyan women. Here, we report findings of this trial through 3 years of follow-up. Overall, 2,275 healthy women aged 15-20 years were recruited and randomly assigned to receive bivalent (n = 760), nonavalent (n = 758) or control (n = 757) vaccine. The primary outcome was incident-persistent vaccine type-specific cervical HPV infection. The primary evaluation was superiority analysis in the modified intention-to-treat (mITT) HPV 16/18 and HPV 16/18/31/33/45/52/58 cohorts. The trial met its prespecified end points of vaccine type-specific persistent HPV infection. A total of 75 incident-persistent infections were detected in the HPV 16/18 mITT cohort: 2 in the bivalent group, 1 in the nonavalent group and 72 in the control group. Nonavalent VE was 98.8% (95% CI 91.3-99.8%, P < 0.0001) and bivalent VE was 97.5% (95% CI 90.0-99.4%, P < 0.0001). Overall, 89 persistent infections were detected in the HPV 16/18/31/33/45/52/58 mITT cohort: 5 in the nonavalent group and 84 in the control group; nonavalent VE was 95.5% (95% CI 89.0-98.2%, P < 0.0001). There were no vaccine-related severe adverse events. Three years after vaccination, single-dose HPV vaccination was highly efficacious, safe and conferred durable protection. ClinicalTrials.gov no. NCT03675256 .

Human papillomavirus vaccine effectiveness by age at vaccination: A systematic review

Human papillomavirus (HPV) vaccines work by preventing infections prior to natural exposure. Thus, it is likely more effective at younger ages, and it is important to understand how effectiveness might be diminished when administered at older ages. We conducted a systematic review of HPV vaccine effectiveness studies published between 2007 and 2022 that included an analysis of effectiveness against vaccine-type HPV infections, anogenital warts, cervical abnormalities and cervical cancer by age at vaccine initiation or completion. Searching multiple databases, 21 studies were included and results were summarized descriptively. Seventeen studies found the highest vaccine effectiveness in the youngest age group. Vaccine effectiveness estimates for younger adolescents ages 9-14 years ranged from approximately 74% to 93% and from 12% to 90% for adolescents ages 15-18 years. These results demonstrate that the HPV vaccine is most effective against HPV-related disease outcomes when given at younger ages, emphasizing the importance of on-time vaccination.

High prevalence of vaccine-preventable anal human papillomavirus infections is associated with HIV infection among gay, bisexual, and men who have sex with men in Nairobi, Kenya

BACKGROUND

Human papillomavirus (HPV) infection is associated with anal cancers and is more prevalent in gay, bisexual, and men who have sex with men (gbMSM), partly due to their vulnerability to HIV infection. Baseline HPV genotype distributions and risk factors can inform the design of next-generation HPV vaccines to prevent anal cancer.

METHODS

A cross-sectional study was conducted among gbMSM receiving care at a HIV/STI clinic in Nairobi, Kenya. Anal swabs were genotyped using a Luminex microsphere array. Multiple logistic regression methods were used to identify risk factors for four HPV outcomes (any HPV, any HR-HPV, and 4- and 9-valent vaccine-preventable HPVs).

RESULTS

Among 115 gbMSM, 51 (44.3%) were HIV-infected. Overall HPV prevalence was 51.3%; 84.3% among gbMSM living with HIV and 24.6% among gbMSM without HIV (p < 0.001). One-third (32.2%) had HR-HPV and the most prevalent vaccine-preventable HR-HPV genotypes were 16, 35, 45, and 58. HPV-18 was uncommon (n = 2). The 9-valent Gardasil vaccine would have prevented 61.0% of HPV types observed in this population. In multivariate analyses, HIV status was the only significant risk factor for any HPV (adjusted odds ratio [aOR]:23.0, 95% confidence interval [95% CI]: 7.3-86.0, p < 0.001) and for HR-HPV (aOR: 8.9, 95% CI: 2.8-36.0, p < 0.001). Similar findings were obtained for vaccine-preventable HPVs. Being married to a woman significantly increased the odds of having HR-HPV infections (aOR: 8.1, 95% CI: 1.6-52.0, p = 0.016).

CONCLUSIONS

GbMSM living with HIV in Kenya are at higher risk of anal HPV infections including genotypes that are preventable with available vaccines. Our findings support the need for a targeted HPV vaccination campaign in this population.