RIO DE JANEIRO – A treatment developed by researchers with Brazil’s Oswaldo Cruz Foundation, or Fiocruz, and tested in Argentina, Brazil, the United States and South Africa has managed to reduce the transmission of AIDS from infected mothers to their children, officials said.

The method, a new combination of medicines, was developed by scientists from Fiocruz, a medical research center linked to the Brazilian Health Ministry, and from the University of California, the foundation said.

The study lasted eight years and involved patients at 17 hospitals in the four countries, most of them – 70 percent – Brazilians.

The experiments showed that the combination of two or three medicines significantly reduces the risk that mothers carrying the virus that causes AIDS will infect their newborns.

The treatment currently recommended by the World Health Organization, or WHO, to avoid the so-called vertical transmission from mother to child consists of administering the antiretroviral AZT to the baby in the first 48 hours after birth.

That therapy reduces the risk of infection of the newborns to 5 percent.

The Brazilian method consists of administering a combination of AZT with nevirapina, another antiretroviral, and a mixture of AZT with nelfnavir and lamiduvine.

The combination of the two medicines reduces the risk to 2.2 percent and the combination of three medicines to 2.4 percent.

The treatment with three medicines, however, was the one that resulted in better collateral effects.

The method was tested in recently-born children of mothers who were only diagnosed as being carriers of the HIV virus causing AIDS shortly before giving birth and, for that reason, they had not been treated with AZT during their pregnancies.

Of the 1,684 babies in the study, 97 were infected with HIV during the pregnancy and 43 during birth.

The Health Ministry has already recommended the adoption of the two-medicine combination in Brazil’s public hospitals.