Questions about what percentage of Africa's HIV infections are caused by dirty needles has prompted U.S. Health and Human Services Secretary Tommy Thompson -- who is also the chairman of the Global Fund to Fight AIDS, Tuberculosis and Malaria -- to order a review of all research linking HIV/AIDS and medical injections, Associated Press has reported. The review could affect how funding from the $15 billion U.S. initiative to fight HIV/AIDS in Africa and the Caribbean is distributed, AP reported.