* AIDS drugs being given to more HIV positive pregnant women
* But children's access to treatment is "unacceptably low"
* New infections in children in Nigeria, Angola a concern
By Kate Kelland
LONDON, June 25 (Reuters) - Seven countries in sub-Saharan Africa, the world's worst-hit region in the global AIDS epidemic, have cut the number of new HIV infections in children by 50 percent since 2009, the United Nations AIDS programme said on Tuesday.
The dramatic reductions - in Botswana, Ethiopia, Ghana, Malawi, Namibia, South Africa and Zambia - mean tens of thousands more babies are now being born free of HIV, UNAIDS said in a report on its Global Plan to tackle the disease in around 20 of the worst affected countries.
Overall, across 21 priority countries in Africa, there were 130,000 fewer new HIV infections among children in 2012 - a drop of 38 percent since 2009 - mostly due to increased drug treatment of pregnant women with the virus.
"The progress in the majority of countries is a strong signal that with focused efforts every child can be born free from HIV," said Michel Sidibé, UNAIDS' executive director.
"But progress has stalled in some countries with high numbers of new HIV infections. We need to find out why and remove the bottlenecks which are preventing scale-up."
Among places causing concern, UNAIDS said, are Angola and Nigeria, where new infections in children have increased and remained unchanged respectively since 2009.
Nigeria has the largest number of children acquiring HIV in the region, with nearly 60,000 new infections in 2012.
And for those children who do become infected, access to AIDS drugs that can keep their disease in check is "unacceptably low", UNAIDS said, with only 3 in 10 children getting the AIDS medicines they need in most priority countries.
The report said much of the reduction in new HIV cases in children was thanks to more use of AIDS drug treatment for HIV-positive pregnant women. Coverage rates were above 75 percent in many of the priority countries, it said.
AIDS medicines known as antiretroviral therapy not only improve the health of mothers with the human immunodeficiency virus (HIV) that causes AIDS, but can also prevent HIV from being transmitted to their children.
Botswana and South Africa have reduced mother to child HIV transmission rates to 5 percent or less, according to UNAIDS.
Eric Goosby, global AIDS coordinator for the United States government, called on the international community to "continue working together to see the day when no children are born with HIV, which is within our reach". (Editing by Alison Williams)