Medical experts recommend that adults keep their vaccinations current. According to Janis Hootman, president of the National Association of School Nurses, many adults have the false impression that vaccinations are exclusively for young children when, in fact, adults are just as susceptible to preventable diseases such as tetanus and diphtheria. The Centers for Disease Control reports that 70 percent of U.S. tetanus and diphtheria cases in the last two decades were among people 40 or older. Indeed, U.S. adults over age 60 run a higher risk of suffering from tetanus because they did not receive regular boosters either as an adult or a child. Hootman says adults need to recognize their vulnerability to these diseases. In addition to tetanus, experts recommend that adults that have not yet had or been vaccinated against chickenpox be immunized.