A reduction in the number of sexual partners per person has helped drive a 50 percent decline in new cases of HIV in Zimbabwe from 1997 to 2007, said an international study published this week in the United States.

The analysis of social factors that helped to halve what was once one of the worst AIDS epidemics in the world could offer lessons for other nations struggling with HIV rates, the study authors suggested.

They say the evidence suggests that “in Zimbabwe, as elsewhere, partner reduction appears to have played a crucial role in reversing the HIV epidemic.”

The report, partly funded by the UNFPA and the US State Department’s development aid agency, USAID, backs the research of Harvard academic Edward C.Green, who affirmed statements made by Pope Benedict in 2009 to the effect that behavioural changes rather than Government condom distribution programmes were the way to reduce AIDS prevalence.

The Pope was condemned by a range of international politicians, including the German, French and Belgian health ministers.

However, the latest research appears to confirm that reducing the number of sexual partners per person is what causes a decline in the prevalance of the disease.

“Today’s findings strongly show that people in Zimbabwe have primarily been motivated to change their sexual behaviour because of improved public awareness of AIDS deaths and a subsequent fear of contracting the virus,” said the study.

The researchers said that these attitude changes were rooted in mass media campaigns that infiltrated church settings, workplaces and other activities.

The prevalence rate in the troubled East African nation peaked in the late 1990s and has been falling since then, according to Daniel Halperin, PhD, of Harvard School of Public Health, and colleagues.

An analysis of the factors that might have been involved in the change suggests that fear of the infection drove men and women to change their sexual behaviour and attitudes, the researchers reported online in PLoS Medicine.