[MPB]

Found this at http://www.slu.edu/colleges/sph/bioterrorism/quick/smallpox01.pdf

"Approximately half of the US population has never been vaccinated • For those who were vaccinated, it is not known how long immunity lasts (most estimates suggest 3-5 years); meaning that nearly the entire US population has partial immunity at best • Immunity can be boosted effectively with a single revaccination • Prior infection grants lifelong immunity"

[nopardons]

I, as many of my generation , was vacinated as a baby, and have had at least one booster. I certainly hope that I am covered for the rest of my life.