<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-09-22T21:42:01Z</responseDate><request verb="GetRecord" identifier="oai:www.repository.cam.ac.uk:1810/273803" metadataPrefix="uketd_dc">https://api.repository.cam.ac.uk/server/oai/request</request><GetRecord><record><header><identifier>oai:www.repository.cam.ac.uk:1810/273803</identifier><datestamp>2024-06-26T13:56:39Z</datestamp><setSpec>com_1810_261990</setSpec><setSpec>com_1810_34581</setSpec><setSpec>col_1810_261993</setSpec></header><metadata><uketd_dc:uketddc xmlns:uketd_dc="http://naca.central.cranfield.ac.uk/ethos-oai/2.0/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:uketdterms="http://naca.central.cranfield.ac.uk/ethos-oai/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://naca.central.cranfield.ac.uk/ethos-oai/2.0/ http://naca.central.cranfield.ac.uk/ethos-oai/2.0/uketd_dc.xsd">
   <dc:title>Estimating HIV incidence from multiple sources of data</dc:title>
   <dc:identifier xsi:type="dcterms:DOI">10.17863/CAM.20872</dc:identifier>
   <dc:creator>Brizzi, Francesco</dc:creator>
   <uketdterms:advisor>De Angelis, Daniela</uketdterms:advisor>
   <uketdterms:advisor>Birrell, Paul</uketdterms:advisor>
   <dcterms:abstract>This thesis develops novel statistical methodology for estimating the incidence and the
prevalence of Human Immunodeficiency Virus (HIV) using routinely collected surveillance
data. The robust estimation of HIV incidence and prevalence is crucial to correctly evaluate
the effectiveness of targeted public health interventions and to accurately predict the HIV-
related burden imposed on healthcare services.

Bayesian CD4-based multi-state back-calculation methods are a key tool for monitoring the
HIV epidemic, providing estimates of HIV incidence and diagnosis rates by disentangling
their competing contribution to the observed surveillance data. Improving the effectiveness
of public health interventions, requires targeting specific age-groups at high risk of infection;
however, existing methods are limited in that they do not allow for such subgroups to be
identified.

Therefore the methodological focus of this thesis lies in developing a rigorous statistical
framework for age-dependent back-calculation in order to achieve the joint estimation of
age-and-time dependent HIV incidence and diagnosis rates. Key challenges we specifically
addressed include ensuring the computational feasibility of proposed methods, an issue that
has previously hindered extensions of back-calculation, and achieving the joint modelling
of time-and-age specific incidence. The suitability of non-parametric bivariate smoothing
methods for modelling the age-and-time specific incidence has been investigated in detail
within comprehensive simulation studies.

Furthermore, in order to enhance the generalisability of the proposed model, we developed
back-calculation that can admit surveillance data less rich in detail; these handle surveillance
data collected from an intermediate point of the epidemic, or only available on a coarse scale,
and concern both age-dependent and age-independent back-calculation.
The applicability of the proposed methods is illustrated using routinely collected surveillance
data from England and Wales, for the HIV epidemic among men who have sex with men
(MSM).</dcterms:abstract>
   <uketdterms:institution>University of Cambridge</uketdterms:institution>
   <dcterms:issued>2018-02-06</dcterms:issued>
   <dc:type>Thesis</dc:type>
   <uketdterms:qualificationlevel>Doctoral</uketdterms:qualificationlevel>
   <uketdterms:qualificationname>Doctor of Philosophy (PhD)</uketdterms:qualificationname>
   <dc:language>en</dc:language>
   <uketdterms:sponsor>MRC BSU</uketdterms:sponsor>
   <dcterms:isReferencedBy xsi:type="dcterms:URI">https://www.repository.cam.ac.uk/handle/1810/273803</dcterms:isReferencedBy>
   <dc:identifier xsi:type="dcterms:URI">https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/6aeb1fd7-4ad4-4f92-951b-dd0bb64d84b4/download</dc:identifier>
   <uketdterms:checksum xsi:type="uketdterms:MD5">7ff5af2d7093db9474ed80aa5163c18d</uketdterms:checksum>
   <dcterms:license>https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/22517fc9-88f2-44f9-a132-ad832e9c42b2/download</dcterms:license>
   <uketdterms:checksum xsi:type="uketdterms:MD5">87eda9de84448d1f82354d60eee3eb5f</uketdterms:checksum>
   <dc:rights>https://creativecommons.org/licenses/by-nc-sa/4.0/</dc:rights>
   <dc:subject>HIV</dc:subject>
   <dc:subject>incidence</dc:subject>
   <dc:subject>undiagnosed prevalence</dc:subject>
   <dc:subject>back-calculation</dc:subject>
   <dc:subject>age-specific</dc:subject>
   <dc:subject>splines</dc:subject>
   <dc:subject>multi-state model</dc:subject>
</uketd_dc:uketddc>
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