Researchers at Saint Louis University are trying to determine the benefit to grown ups of having been vaccinated against smallpox as children. Routine smallpox vaccinations for children were conducted in Missouri and elsewhere up until the 1970s, when smallpox was declared eradicated. Doctor Sharon Frey, an associate professor at Saint Louis University School of Medicine and the lead author of a study on the effectiveness of those shots all these years later, says there appears to be some benefit. But, the vaccine becomes less potent as time goes on. Doctor Frey says that while a previously vaccinated person would not be immune to smallpox, that person might be protected from developing a severe case of the disease.