A study conducted in Kenya, Malawi and Tanzania analysed the relationship between malaria and HIV prevalence adjusting for important socio-economic and biological cofactors. This is the first study to report malaria as a risk factor of concurrent HIV infection at the population level. Use was made of large nationally representative samples of 19 735 sexually active adults from the 2003–2004 HIV/AIDS indicator surveys. Results showed that individuals who live in areas with high Plasmodium falciparum parasite rate had increased estimated odds of being HIV positive than individuals who live in areas with low P. falciparum parasite rate (adjusted odds ratio (OR) of 2.2, 95% confidence interval (CI) of 1.6–3.1 in men and OR=2.4, 95% CI [1.9–3.2] in women).
So individuals who live in areas with high P. falciparum parasite rate have about twice the risk of being HIV positive compared with individuals who live in areas with low P. falciparum parasite rate. This study emphasizes the need for field studies focused on quantifying the interaction among malaria and other parasitic infections and the risk of HIV infection, and studies to explore the impact of control interventions.