Vaccinating pregnant women for flu helps protect their babies from the disease after birth, is safe and could point the way to other such vaccines, according to Baylor medical school researchers.

Thirteen women in a Baylor College of Medicine study were immunized against flu in the last trimester of pregnancy, and each gave birth to an infant with high levels of antibodies to the influenza virus, Dr. Janet Englund reported Tuesday in Atlanta at the Interscience Conference on Antimicrobial Agents and Chemotherapy.The conference is sponsored by the American Society for Microbiology.

None of the mothers or infants had complications from the vaccine, and while flu antibodies produced by the mother's body were imparted to children in the womb, there was no evidence that the vaccine itself reached the fetus, Englund said.

"Maternal immunization to protect the infant during the first months of life appears to be safe and feasible," Englund reported.

Maternal immunizations were performed by some physicians in the 1960s, but fell out of favor amid concerns over complications. Baylor researchers said their study shows protection can be safely passed along in the womb, without passing along vaccine that isn't necessarily appropriate in the fetus.

Researchers believe flu immunity passed from a mother to child lasts about four months, providing crucial protection in the earliest stages of life, Englund said.

"This is a model for other vaccines," she said, adding that vaccines against whooping cough and Haemophilus influenza B - Hib disease, a leading cause of meningitis - might be used similarly. Those diseases kill large numbers of infants in developing countries.

"We'd like this to be a Third World shot - one that could be used to help the mother and the baby," she said.