The 12 African countries that receive most of the American taxpayer dollars spent fighting AIDS could do much more to pay their own way, according to a new study.

But even if all 12 made what the study’s authors considered the maximum effort, most would still need help because they collect so little in taxes and have other pressing needs, like paved roads.

The study, by the Harvard School of Public Health and the Results for Development Institute in Washington, was published in the January issue of The Lancet Global Health and paid for by the Centers for Disease Control and Prevention.

The wealthiest three — South Africa, Namibia and Botswana — could pay their own way soon “without too much fiscal pain,” said Robert Hecht, the institute’s managing director and a co-author. Self-reliance by the poorer countries is “pretty timid,” he said, “but even Mozambique could be spending five to 10 times what it does on health and AIDS.”