Preventive medicine
-
Preventive medicine · Mar 2021
ReviewReducing cervical cancer deaths in women living with HIV: PEPFAR and the Go Further partnership.
Women with HIV bear a significant burden of Human Papillomavirus (HPV) related cervical disease, and a have a higher risk of dying from cervical cancer should it occur. WLH have increased acquisition of HPV and decreased clearance, leading to persistent HPV infection: a risk for cervical cancer. The greatest burden of HIV in women occurs in sub-Saharan Africa where diagnostic and treatment services for cervical disease are limited. This paper will describe the epidemiology of HPV related cervical disease in women living with HIV (WLH) and the efforts to treat precursor lesions in HIV treatment programs supported by the President's Emergency Plan for AIDS Relief (PEPFAR.
-
Preventive medicine · Mar 2021
ReviewElimination of cervical cancer: Lessons learned from polio and earlier eradication programs.
This paper reviews definitions of control, elimination, and eradication and considers lessons learned from prior and current elimination/eradication efforts that might inform the current effort to eliminate cervical cancer. This task is complicated by the varying definitions of elimination extant. Lessons for cervical cancer elimination notably include the necessity for political will/champions; the need for a specific target with a time span; the need for program efforts to be guided by surveillance of disease and death (not just coverage); the need for accountability, monitoring, and evaluation at all levels; and the need for ongoing research. Although achieving the goal of elimination will be difficult, success will mean the prevention of millions of deaths due to cervical cancer.
-
Preventive medicine · Mar 2021
A proposed new generation of evidence-based microsimulation models to inform global control of cervical cancer.
Health decision models are the only available tools designed to consider the lifetime natural history of human papillomavirus (HPV) infection and pathogenesis of cervical cancer, and the estimated long-term impact of preventive interventions. Yet health decision modeling results are often considered a lesser form of scientific evidence due to the inherent needs to rely on imperfect data and make numerous assumptions and extrapolations regarding complex processes. We propose a new health decision modeling framework that de-emphasizes cytologic-colposcopic-histologic diagnoses due to their subjectivity and lack of reproducibility, relying instead on HPV type and duration of infection as the major determinants of subsequent transition probabilities. ⋯ Evidence for this variability in host response to HPV infections can be inferred from HPV prevalence patterns in different regions across the lifespan, and might be linked to different average population levels of immunologic control of HPV infections. By prioritizing direct estimation of model transition probabilities from longitudinal data (and limiting reliance on model-fitting techniques that may propagate error when applied to multiple transitions), we aim to reduce the number of assumptions for greater transparency and reliability. We propose this new microsimulation model for critique and discussion, hoping to contribute to models that maximally inform efficient strategies towards global cervical cancer elimination.
-
Preventive medicine · Mar 2021
Current and future vaccine clinical research with the licensed 2-, 4-, and 9-valent VLP HPV vaccines: What's ongoing, what's needed?
Prophylactic HPV vaccination has been a great public health success. For >20 years, clinical trials were conducted with the 2-, 4-, and/or 9-valent vaccines in young-adult females, mid-adult women, males, and adolescents. In all studies, the vaccines were highly efficacious, immunogenic, and well tolerated. ⋯ Thirty-eight clinical trials with the currently licensed HPV vaccines are ongoing. Key questions being addressed in new trials include: efficacy against persistent infection and immunogenicity of a 1-dose regimen; efficacy of 3 doses in 20-45-year-old females; use in postpartum women and immunocompromised individuals (HIV, liver and kidney transplants); dose sparing via intradermal administration; use in combination with a PD1 monoclonal antibody in patients with cervical cancer; impact on recurrent disease in women undergoing cervical conization; persistence of protection; and use to prevent oropharyngeal cancer. Additional clinical research that should be conducted includes: long-term follow-up, particularly of 1- and 2-dose regimens; further evaluation of flexible 2-dose regimens; immunogenicity of 1- or 2-dose regimens in persons ≥15 years old and immunocompromised populations; safety and immunogenicity of 1 or 2 doses in children <9 years old; assessment of the vaccine in the prevention of transmission; interchangeability with newer HPV vaccines; additional concomitant use studies; and prevention of penile cancer and recurrent respiratory papillomatosis.
-
Preventive medicine · Mar 2021
Achieving equity in cervical cancer screening in low- and middle-income countries (LMICs): Strengthening health systems using a systems thinking approach.
The World Health Organization (WHO) is leading a call to action to eliminate cervical cancer by the end of the century through global implementation of two effective evidence-based preventive interventions: HPV vaccination and cervical screening and management (CSM). Models estimate that without intervention, over the next 50 years 12.2 million new cases of cervical cancer will occur, nearly 60% of which are preventable only through CSM. Given that more than 80% of the cervical cancer occurs in low- and middle-income countries (LMICs), scaling up sustainable CSM programs in these countries is a top priority for achieving the global elimination goals. ⋯ As part of the coordinated cervical cancer elimination effort, we applied a systems thinking lens to reflect on our experiences with implementation of HPV-based CSM programs using the WHO health systems framework. While many common health system barriers were identified, the effectiveness of implementation strategies to address them was context dependent; often reflecting differences in stakeholder's belief in the quality of the evidence supporting a CSM algorithm, the appropriateness of the evidence and algorithm to context, and the 'implementability' of the algorithm under realistic assessments of resource availability and constraints. A structured planning process, with early and broad stakeholder engagement, will ensure that shared-decisions in CSM implementation are appropriately aligned with the culture, values, and resource realities of the setting.