 The purpose of this study is to see if taking nevirapine NVP for HIV changes the way artemetherlumefantrine AL works in children who are co-infected with both HIV and malaria. The brand of AL used in this study is Coartem Dispersible. This study will compare the blood levels of AL in co-infected children who already take NVP prescribed by their doctor with the co-infected children who do not take anti HIV medicines because they do not meet national guidelines to start them. The study will also assess the safety of using both medications AL and NVP in children. 