单选题 Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases, says the CDC's emphasis on hand -washing is guided by the" science that supports hand-washing against respiratory infections in general. "In particular, she cites a study conducted in Pakistan that showed that hand hygiene measures cut the rate of pneumonia in half. One of the unique features of swine flu - the fact that it causes diarrhea- also suggests to some that it could be transmitted on the hands like other diarrhea - causing diseases that do not belong to the influenza family. Schuchat stresses that the best way to protect yourself will be to get the vaccine once it becomes available in October, but adds that the CDC continues to believe that "contact precautions are useful with this flu. "
According to Schuchat

• A. hand-washing is useful with H1N1 flu.
• B. the only way to protect one against H1N1 is to get the vaccine.
• C. the emphasis on hand -washing has no scientific ground.
• D. hand - washing can only reduce the rate of pneumoni