HOUSTON, Dec. 1 (Xinhua) -- A decrease of A/H1N1 flu activity and an increase of vaccine supply in recent weeks opened a "window of opportunity" to protect American people against the ongoing pandemic disease, a high-ranking U.S. health official said on Tuesday.

    "We're going from a time where there was lots of disease and not enough vaccines, to a time where disease is gradually decreasing and we're having a steady increase in the amount of vaccine available," Thomas R. Frieden, director of the U.S. Centers for Disease Control and Prevention (CDC), told a press conference.

    The CDC said on Monday the number of states that had widespread A/H1N1flu activity during last week hit a record low of 32 since September. Visits to doctors by patients with flu symptoms had declined for the fourth straight week.

    Meanwhile, about 70 million doses of A/H1N1 flu vaccine are now available, and the supply continues to increase.

    "That leaves a window of opportunity for people to be protected by getting the vaccine in case there's another surge or wave in future months," said the CDC director.

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