Re: US plans to increase smallpox vaccine stocks
from http://www.dhmh.state.md.us/phdsec/html/phalert.htm#smallpox
"Routine vaccination against smallpox in the United States of America was discontinued in 1972. Few persons younger than 29 years of age have been vaccinated. Also, the level of immunity among persons older than 29 in the United States is uncertain. The duration of immunity has not been well measured. It must be assumed that the population at large is highly susceptible to infection. "
I think this is official CDC information.
tony - in a jittery mood after surfing for smallpox and anthrax