High patient acceptability but low coverage of provider-initiated HIV testing among adult outpatients with symptoms of acute infectious illness in coastal Kenya by Agutu, CA, Oduor, TH, Kombo, BK, Mugo, PM, Chira, SM, Ogada, FW, Rinke de Wit, TF, Chege, W, van der Elst, EM, Graham, SM, Sanders, EJ