Pediarix, GlaxoSmithKline's new vaccine that combines five childhood immunizations into one shot, received FDA approval in December. Some parents believe reducing the number of vaccinations children must endure reduces trauma, but other parents are worried about safety and the possibility that so many vaccinations at one time will overload infant immune systems. University of California-Los Angeles Center for Vaccine Research Director Joel Ward, who led Pediarix's clinical trials, asserts that combination vaccines are safe and effective for children and casts doubt on a connection between combination vaccinations and the development of autism.