That’s what happened to the patient in the new report, a 29-year-old white man who was given the vaccine as an infant. (The man has never developed the disease itself.
The viruses in the patient’s gut were able to cause paralysis in a mouse model, suggesting that these strains are very virulent.
Strains of polio that differ from those in the vaccine have been found in sewage samples from Slovakia, Finland, Estonia and Israel, the researchers said. These findings suggest that “an unknown number of these chronic excreters exist elsewhere,” the researchers said.