pv3

After just over two years of rigorous and closely monitored field trials and coincidentally on what was the tenth anniversary of the death of US President Franklin Delano Roosevelt (see previously) whose progressive and ultimately fatal paralytic illness was believed to be caused by an onset of a childhood case of the disease, the polio vaccine that Doctor Jonas Salk and his team at the University of Pittsburgh was declared safe and effective on this day in 1955 and approved for general use against strains the debilitating virus. Although transmission does still occur in parts of the developing world, the incidence of contagion has been interrupted, decimated by mass-intervention—numbers in the United States alone saw a precipitous drop, falling from thirty-five thousand cases in 1953 to fifty-six hundred in 1957 and less than two hundred four years later.