Immunization Newsbriefs (c) Copyright Information Inc., Bethesda, MD. Brought to you by the National Network for Immunization Information (NNii). Visit NNii's new website at http://www.immunizationinfo.org.

———————————————————————

May 21, 2003

U.S. IMMUNIZATION NEWS

“Study: Smallpox Immunity Remains in Body for Years After Vaccination”

USA Today (www.usatoday.com) (05/21/03) P. 7D; Manning, Anita

A new study by Oregon Health and Science University researcher Mark K. Slifka found that over 90 percent of 306 people had the same range of antibodies to vaccinia, the live virus used in the smallpox vaccine, no matter if they were recently vaccinated or vaccinated as far back as 1928. However, Slifka did note that there was a decrease in white blood cells, which are needed for full protection against smallpox, in older people. The study also found that people who received a smallpox immunization and then a booster shot had greater immunity, but more than two shots showed no significant improvement in immunity.  The results of the study, which were presented Tuesday at a meeting of the American Society for Microbiology in Washington, D.C., are preliminary and support a previous small study which showed a long-term immune response over 35 years.