Jonas Salk was against mercury being added to his vaccine. Other preservatives existed even then.
Until the morning of April 12, Salk himself did not know the trial's results, which his colleague Francis had completed and kept secret. Salk was nervous, his son said. "There had been a lot of pressure from the March of Dimes to make this a reality because it was such a hugely frightening disease," Peter Salk explained. Among almost 52,000 cases in 1952, for example, 21,000 resulted in paralysis. In addition, the U.S. government had recommended at the last minute before the trial that Merthiolate be added to the vaccine. Popularly called "monkey blood" back then, this deep red liquid was a mercury and sodium tincture used by moms and grandmothers everywhere to kill bacteria on cuts and scrapes. Adding it to the vaccine would kill any bacteria or fungi in the vials. Today, this preservative is better known by its generic name, thimerosal.Salk had not had time to test the vaccine's effectiveness with the preservative and worried about whether it would decrease the formulation's immunogenicity, the ability to induce an immune response.
Jonas Salk was against mercury being added to his vaccine. Other preservatives existed even then.Until the morning of April 12, Salk himself did not know the trial's results, which his colleague Francis had completed and kept secret. Salk was nervous