Combinations of anti-AIDS drugs given to adults infected with HIV can also be effective in newborns, in whom the virus tends to be more aggressive, according to a new report on Wednesday.

The finding may help guide HIV treatment in the youngest children. More than 2000 babies are born each day with the virus, 90 percent of them in developing countries.

Current U.S. guidelines only suggest multidrug treatment for children under 1 year old who have been infected with the AIDS virus but have no signs or symptoms of the disease.

The new study in Thursday’s issue of The New England Journal of Medicine, and other research, “provide increasing evidence that several regimens of antiretroviral therapy are safe, effective, and well tolerated during years of administration when started in infancy,” said Katherine Luzuriaga of the University of Massachusetts Medical School in Worcester.

The report used data from 25 medical centers in the United States and Puerto Rico.

It found that babies who started the multidrug treatment before they were three months old were twice as likely to have low levels of the AIDS virus in their blood after nearly four years compared to babies who began later.

Three different combinations of drugs were tested on the children.

There have been suggestions that intensive treatment during the first year of life could make HIV easier to treat later on. The Luzuriaga group found no evidence to support that, and reported that the virus seems able to fight back aggressively at any time.