Source: New York Times
By: McNeil, Jr., Donald G.
Researchers at the State University of New York at Stonybrook have created new strains of polio that generate an immune reaction just like the live viruses used to make the vaccine but pose no risk if they somehow enter the population. These new strains aim to protect workers in factories that manufacture the polio vaccine. Lead researcher and molecular geneticist Eckard A.F. Wimmer says the live viruses used in the injectable Salk vaccine are killed with formaldehyde to ensure the finished product is safe, but if a leak, explosion, or natural disaster were to cause the growing live viruses to escape, he says “the spill could spread like wildfire.” There is a need to create safer seed strains of virus, given that the phasing out of the oral Sabin vaccine means more doses of the injectable version must be produced. The researchers mutated a part of the virus’ RNA needed for growth and weakened it, then inserted it in a part of the RNA that controls virulence. Thus, Wimmer says the virus would not do any harm if it enters the brain, and he adds that the virus would hurt its own ability to reproduce if it were to evolve to overpower the virulence-lowering mutation. He hopes the new vaccine will ultimately be combined with those for measles, diphtheria, and other diseases and be administered in a single, painless, jet injector shot.