Preventive medicine
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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.
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Preventive medicine · Mar 2021
HPV vaccination introduction worldwide and WHO and UNICEF estimates of national HPV immunization coverage 2010-2019.
WHO/UNICEF estimates for HPV vaccination coverage from 2010 to 2019 are analyzed against the backdrop of the 90% coverage target for HPV vaccination by 2030 set in the recently approved global strategy for cervical cancer elimination as a public health problem. As of June 2020, 107 (55%) of the 194 WHO Member States have introduced HPV vaccination. The Americas and Europe are by far the WHO regions with the most introductions, 85% and 77% of their countries having already introduced respectively. ⋯ When expressed as world population coverage (i.e., weighted by population size), global coverage of the final HPV dose for 2019 is estimated at 15%. There is a long way to go to meet the 2030 elimination target of 90%. In the post-COVID era attention should be paid to maintain the pace of introductions, specially ensuring the most populous countries introduce, and further improving program performance globally.
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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.
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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.
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Preventive medicine · Mar 2021
The role and utility of population-based cancer registries in cervical cancer surveillance and control.
Population-based cancer registries (PBCR) are vital to the assessment of the cancer burden and in monitoring and evaluating national progress in cervical cancer surveillance and control. Yet the level of their development in countries exhibiting the highest cervical cancer incidence rates is suboptimal, and requires considerable investment if they are to document the impact of WHO global initiative to eliminate cervical cancer as a public health problem. As a starting point we propose a comprehensive cancer surveillance framework, positioning PBCR in relation to other health information systems that are required across the cancer control continuum. ⋯ Linking cervical cancer data to screening and immunization information systems enables the development of a comprehensive set of measures capable of assessing the short- and long-term achievements and impact of the initiative. Such data form the basis of national and global estimates of the cancer burden and permit comparisons across countries, facilitating decision-making or triggering cancer control action. The initiation and sustainable development of PBCR must be an early step in the scale-up of cervical cancer control activities as a means to ensure progress is successfully monitored and appraised.