As in the race to develop a vaccine, speed is the primary focus. The next day a campaign to produce the polio vaccine began. But within just a few days there were reports of children suffering from polio and even becoming paralyzed after being vaccinated. This is due to incorrect laboratory procedures used by some manufacturers, resulting in some vaccines containing live viruses. Vaccinations continued for weeks despite minimal federal oversight and political pressure. The U.S. Surgeon General did halt vaccinations but eventually more than 10,000 people received a defective vaccine containing live poliovirus.
The government implemented new processes to review laboratory belarusphone number library processes and test all new vaccine shipments to resolve the issues and then restart production. In subsequent years Albert Sabin developed another polio vaccine. His vaccine uses a weakened version of the live virus and is given by mouth rather than by injection. It is difficult to generate interest in clinical trials of new vaccines because the Salk vaccine has already been approved in the United States. So Sabin conducted clinical trials in the Soviet Union and Czechoslovakia, testing the vaccine on more than 10,000 children.
The World Health Organization later verified the clinical trial results. This is important because of the political tension and international distrust during the Cold War. After validation, the Sabin vaccine was quickly found to be a good tool for mass vaccination because it is an oral droplet form. Millions of people have now been safely vaccinated against polio. Vaccine-induced polio is extremely rare. Both polio vaccines are considered very safe. Only the inactivated polio vaccine, the original Salk vaccine, is approved for use in the United States.