In this thesis a diverse range of topics related to paediatric HIV and HCV infection are investigated information is provided on the more specific areas of coinfection, disease monitoring methodologies and the impact of mode of acquisition of infection. Four unique epidemiological cohorts of vertically and parenterally HIV, HCV and HIV/IICV coinfcctcd children are analysed. ALT reference ranges adjusted for age and sex in children under five years of age show that ALT levels greater than 60U/1 in boys and 55U/1 in girls should be regarded as elevated in the first 18 months of life while thereafter the upper limits of normal ALT levels are lower 40U/1 in boys and 35U/1 in girls. There are no differences found between vertically and parenterally HCV-only infected groups in their genotype profile, proportion with consistent viraemia, consistently elevated ALT levels or evidence of two or more markers of disease progression. Parenterally HIV infected children are described for the first time and only 12% found to progress to moderate/severe clinical symptoms or immunosuppression during follow-up. The lack of treatment in this group (11% treated) suggests a more favourable disease progression in parenterally than vertically HIV infected children. The possible detrimental effects of ART on ALT levels in HIV/HCV coinfected children are demonstrated along with the possible need for differential management of children infected via different routes given the faster progression to immunosuppression in parenterally coinfected children. The survey of current practices and policies for care of HIV/HCV coinfected children reveals that in general the management practices vary widely in terms of testing high risk groups for coinfection, which laboratory tests to carry out in comparison to those performed on HIV- only and HCV-only infected children and the opinions on optimal treatment for this group emphasise the importance of research in this area to inform clinical guidelines
