单选题 Fortunately, the new H1N1 virus has been mild so far. Though it has infected a million Americans, only 556 deaths have been reported to date, versus 36,000 a year for the normal seasonal flu. But H1N1 also arrived very late in the last flu season and did not spread through the whole country. This year the vulnerable population will be much larger. The CDC produced a video last year called Why Flu Vaccination Matters. It features interviews with parents. who have lost healthy children to the seasonal flu. Officials plan to update it this year with information on swine flu.
Compared with the normal seasonal flu, H1N1 virus so far has been

• A. more dangerous
• B. mild
• C. fatal
• D. spreading more fast.