Modelling the impact of prevention strategies on cervical cancer incidence in South Africa
type: CreativeWork
description: Background: In 2019, the World Health Organisation called for the elimination of cervical cancer as a public health concern. In South Africa, despite having a national screening policy in place since 2000, diagnosed cervical cancer incidence has shown no signs of decline. Since 2014, girls aged 9 have been vaccinated against HPV infection using the bivalent vaccine, with high coverage. However, due to the long delay between HPV infection and progression to cancer, the impact that vaccination will have on cervical cancer incidence will be unobservable in the near future. This thesis sets out to quantify this impact using a mathematical model, and will estimate the impact of scaling up current cancer prevention strategies, as well as proposed alternative strategies. Methods: This research extends a previously developed individual-based model for HIV to include infection with 13 high-risk HPV types and progression to cervical cancer. HPV infection and cervical disease parameters were calibrated to a wide range of South African data sources using a likelihood based approach. In the process of developing an appropriate model for cervical cancer incidence in South Africa, important aspects related to HIV/HPV co-infection dynamics, the natural history of HPV and the current and historic levels of cervical cancer prevention in the Western Cape were investigated. The calibrated and validated model was used to estimate the impact of current and proposed alternative prevention strategies on cervical cancer incidence in the next century. Findings: Using a model structure that does not include a biological transmission co-factor, we show that simulated associations between HIV and HPV transmission are similar to corresponding empirical estimates and therefore these associations may result from residual confounding by sexual behavioural factors and network-level effects. Using simulated vaccine trials, we show that viral latency and reactivation of latent infections is necessary …
abstract: Background: In 2019, the World Health Organisation called for the elimination of cervical cancer as a public health concern. In South Africa, despite having a national screening policy in place since 2000, diagnosed cervical cancer incidence has shown no signs of decline. Since 2014, girls aged 9 have been vaccinated against HPV infection using the bivalent vaccine, with high coverage. However, due to the long delay between HPV infection and progression to cancer, the impact that vaccination will have on cervical cancer incidence will be unobservable in the near future. This thesis sets out to quantify this impact using a mathematical model, and will estimate the impact of scaling up current cancer prevention strategies, as well as proposed alternative strategies. Methods: This research extends a previously developed individual-based model for HIV to include infection with 13 high-risk HPV types and progression to cervical cancer. HPV infection and cervical disease parameters were calibrated to a wide range of South African data sources using a likelihood based approach. In the process of developing an appropriate model for cervical cancer incidence in South Africa, important aspects related to HIV/HPV co-infection dynamics, the natural history of HPV and the current and historic levels of cervical cancer prevention in the Western Cape were investigated. The calibrated and validated model was used to estimate the impact of current and proposed alternative prevention strategies on cervical cancer incidence in the next century. Findings: Using a model structure that does not include a biological transmission co-factor, we show that simulated associations between HIV and HPV transmission are similar to corresponding empirical estimates and therefore these associations may result from residual confounding by sexual behavioural factors and network-level effects. Using simulated vaccine trials, we show that viral latency and reactivation of latent infections is necessary …
author: van Schalkwyk, Catherina
keywords: Public Health
date published: 2021
date modified: 2026-07-22T22:23:13Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Department of Public Health and Family Medicine

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/36201