Participants will receive free AZT starting at the 36th week of pregnancy and during labor.

"Clearly the potential harm to women receiving AZT cannot be taken lightly," he said.

On the other hand, if the mother has only been receiving AZT for a short time, longer treatment of the newborn might be helpful, they note.

But the infection rate was only 8 percent for those whose mothers received AZT, officials said.

Each newborn then received AZT in a syrup for six weeks.

For comparable periods, the figures were 20 percent and 24.1 percent in the group that received AZT.

There were fewer deaths among those who received AZT in the study, the company said.

Nationwide, about 6,000 patients are now receiving AZT under the Federal grant.

However, many patients receiving AZT continue to contract the pneumonia.

In the clinical trial, only half the participants will get the new drug and the other half will receive the standard treatment, azidothymidine, or AZT.