a1 Department of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, UK
a2 Statistics, Modelling and Economics Department, Center for Infections, Health Protection Agency, UK
a3 Karonga Prevention Study, Chilumba, Malawi
We describe the development of the HIV epidemic in Karonga District, Malawi over 22 years using data from population surveys and community samples. These data are used to estimate the trend in HIV prevalence, incidence and need for antiretroviral treatment (ART) using a simple mathematical model. HIV prevalence rose quickly in the late 1980s and early 1990s, stabilizing at around 12% in the mid-1990s. Estimated annual HIV incidence rose quickly, peaking in the early 1990s at 2·2% among males and 3·1% among females, and then levelled off at 1·3% among males and 1·1% among females by the late 1990s. Assuming a 2-year eligibility period, both our model and the UNAIDS models predicted 2·1% of adults were in need of ART in 2005. This prediction was sensitive to the assumed eligibility period, ranging from 1·6% to 2·6% if the eligibility period was instead assumed to be 1·5 or 2·5 years, respectively.
(Accepted October 31 2006)
(Online publication January 12 2007)
c1 Author for correspondence: Dr R. G. White, Mathematical Epidemiology of Infectious Diseases Group, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. (Email: email@example.com)