BEIJING, Jan. 8 (Xinhua) -- Flu and colds are stalking the Beijing streets with almost 8 percent of patients treated in hospital since Jan. 1 suffering from one or other, according to the Beijing Center for Diseases Control and Prevention (CDC).

    "The number of patients with flu or colds has doubled in many Beijing hospitals, breaking records," said Liu Zejun, director of the CDC.

    Of the 2.3 million patients registered in 67 hospitals in 18 districts and counties in the Beijing area since the municipal disease monitoring system launched on Sept. 1, 2.4 percent are flu sufferers, according to the CDC.

    Since December, the number has risen from 3 percent to nearly 5percent, and hit 8 percent after New Year's Day.

    There were 8,000 outpatients at Beijing Children's Hospital last Friday, 1,000 more than last year, and 7 percent of them were complaining of flu and colds, according to the hospital.

    Similar numbers were seen in many other big hospitals in Beijing and many had to switch into emergency mode.

    Over 6,370 outpatients visited Beijing Chaoyang Hospital last Friday while Boai Hospital doubled its last year's patient number.

    "Not everyone has flu, some just have a common cold. The ratio is not much higher than last year's and will drop in the last 10 days of the month," Liu said.

    An increase of flu and colds in December and January is normal, and "rise" does not mean "explosion", Liu said.

    According to the CDC, the main flu virus this year is very similar to last year's, and the existing vaccination is still effective.

    Around 500,000 people were vaccinated against flu this year, 300,000 less than last year, Liu said.

    The sharp drop in temperature and recent thick "dirty" fog are the main reasons for the rise in cases, said Doctor Wang Zhi from Boai Hospital.

    Experts suggested people visit smaller hospitals and stay at home if they catch a cold to avoid infecting others.