The drugs, made by Gilead Sciences, are the first-line treatment for chronic hepatitis C, which can be deadly. Patients have to take the pills for 12 weeks.
The study was published in PLOS medical journal last week following outrage over the high prices of the drugs.
Some health insurers in the US have refused to pay for it at $84,000 (R1.3-million) for the 12-week course. The US Congress slammed the drug company for its excessive pricing.
In the US a single pill is an outrageous $1,000 - but in India Gilead licensed generic manufacturers to produce it for $4 each.
The study into Gilead's hepatitis medication showed that in 12 of the 30 countries, a year's average wages would be needed for Harvoni or Solvadi for one course.
"Current prices of these medicines are variable and unaffordable globally. These prices threaten sustainability of health systems in many countries and prevent large-scale provision of treatment," the study said.
South Africa was not included in the study as the drug arrived in the country only this year and is yet to be licensed. But it can be imported on a case-by-case basis with permission from the Medicines Control Council.
Doctors have lobbied Gilead to reduce the price and succeeded in getting the drug reduced to between $900 and $1,200 for the 12-week course - a 100th of the US price.
University of Cape Town's professor Mark Sonderup said Gilead initially wanted to sell the drug at middle-income country rates, but doctors motivated for a different pricing structure because of the high levels of poverty and inequality.
Private patients get it at a 10th of the US price at $10,500 (about R158,407.73) for a 12-week treatment, said Inez Naidoo of Discovery Health Medical Scheme.
Hepatitis drugs are not the only highly priced medicines on the market. Discovery had 13 ultra-high-cost claimants whose medicines were R1-million each a year in 2008. Last year it had 89 high-cost drug claimants at R1.22-million each.