Seasonal vaccine no help against swine flu

ATLANTA (AP) - U.S. health officials say they are "very pessimistic" that the seasonal flu vaccine protects against the unique swine flu infecting people in the United States, Mexico and other countries.

A U.S. Centers for Disease Control and Prevention official said Sunday afternoon that tests of the seasonal vaccine and the new virus show no cross-reaction, suggesting that people who got the vaccine have no added protection against the new bug. It's possible that people who have been exposed to flu viruses every year - especially older people, with a greater exposurehistory - may have some natural immunity, the CDC official said in a call with reporters.

Meanwhile, the U.S. has declared a public health emergency as it deals with a deadly new strain of swine flu. There have been 20 U.S. cases so far, all non-fatal. The federal plan calls forseveral steps, including moving a flu-drug stockpile to areas whereit can be used quickly if needed.

Go to WebMD for frequently asked questions about swine flu.

(Copyright 2009 by The Associated Press. All Rights Reserved.)