Flu Shot Kick-Starts Fetal Immune System

(HealthDay News) -- Giving flu vaccinations to a pregnant woman kick-starts the immune system of her fetus, a U.S. study says.

The researchers, led by Rachel Miller of the Columbia University Medical Center, used a newly developed technique called MHC tetramer staining to analyze B- and T-cell immune responses in umbilical cord blood after pregnant women were vaccinated with Fluzone.

Anti-Fluzone antibodies were detected in about 40 percent of the blood cord samples. MHC tetramer staining showed that some of the blood cord samples also made T-cells specifically against the vaccine.

These and other findings in the study establish that B- and T-cell responses to antigens occur in utero after pregnant women have received flu vaccinations, the study authors said. This supports the theory that the human neonatal system can respond to environmental exposures.

The findings have important implications for determining when immune responses to environmental exposures begin, the researchers said.

The study is published in the June 1 issue of the Journal of Clinical Investigation.

Influenza vaccinations for pregnant women are considered safe and are recommended by the U.S. Centers for Disease Control and Prevention.

More information
The March of Dimes Birth Defects Foundation has more about vaccinations during pregnancy