Yes, some viral vaccines contain gelatin to stabilize vaccines so that they remain effective after manufacture. All gelatin contained in vaccines is porcine in origin. However, both leaders of the Jewish and Muslim faiths have declared that pork derived additives in medicines are permitted for those observant of these religions. Rabbi Abraham Adler, from the Kashrus and Medicines Information Service in the United Kingdom has advised that “according to Jewish laws, there is no problem with porcine or other animal derived ingredients in non-oral products. This includes vaccines, injections, suppositories, creams and ointments”. Scholars of the Islamic Organization for Medical Sciences have also determined that the process by which the original pork product is transformed into gluten, alters it enough whereby it is permitted for observers of Muslim faith to receive vaccines.