Drug manufacturers could afford to sell AIDS drugs in Africa at virtually any discount. The companies said they did not do so because Africa lacked the requisite infrastructure.

In Africa through the 1990s, with notable exceptions in Senegal and Uganda, nearly all the ruling powers denied they had a problem with AIDS.

In 1995, Glaxo bought Burroughs Wellcome and became the presumptive leader in AIDS therapy.

Experts said public companies worry about the loss of customer confidence and the legal liability to shareholders or security vendors when they report flaws.

For a decade, makers of AIDS medicines had rejected the idea of lowering prices in poor countries for fear of eroding profits in rich ones. The position required a balancing act, because the companies had to deflect attacks on the global reach of their patents, which granted exclusive marketing rights for antiretroviral drugs.

Early in 1986, the World Health Organization in Geneva still regarded AIDS as an ailment of the promiscuous few.