The United Nations says the number of new HIV infections has dropped by one quarter in 22 of the most affected countries in Sub-Saharan Africa.

Officials with the U.N. AIDS organization said Friday that countries with the largest epidemics in Africa are leading the drop in the number of infections.  Those include Ivory Coast, Ethiopia, Nigeria, South Africa, Zimbabwe and Zambia.

The U.N. says young people are playing a critical role in preventing the disease, by choosing to have sex later, having fewer partners and using condoms.

More than 12 times as many people are now receiving medication than six years ago, bringing the number treated to 5.2 million.

By contrast, in Eastern Europe and Central Asia, the number of new HIV infections is growing.  There also is a resurgence of cases among homosexual men in several developed nations.

UNAIDS say the reduction in the number of new HIV infections in Africa is pushing the organization toward its goal of halting or reversing the spread of HIV by 2015.