BEIJING, Sept. 7 (Xinhua) -- The first serious victim of A/H1N1 flu in Shanghai is in a critical condition and suffering from multiple organ failure, doctors said.

    The 35-year-old migrant worker is in a coma at Shanghai No. 1 People's Hospital in Songjiang District, but his temperature and blood pressure are stable, infectious disease expert Dr. Lu Hongzhou was quoted as saying by Monday's Shanghai Daily.

    Five experts from the Ministry of Health are in Shanghai to help local doctors treat the patient, who fell ill last Thursday with severe symptoms and was having difficulty breathing.

    The man was confirmed as contracting A/H1N1 on Friday. Apart from obesity, the patient has no other complicating factors, Lu said.

    Most deaths from A/H1N1 flu are among the very young and middle-aged people. "That's because those groups have a strong immune system, which reacts more actively to the A/H1N1 virus," Lusaid. "A hard fight between virus and immune system can result in greater damage."

    More than 100 people across China were infected with A/H1N1 fluover the weekend, a clear signal that its peak season has begun, Zeng Guang, a senior epidemiologist at the Chinese Center for Disease Control and Prevention, was quoted as saying by Monday's China Daily.

    Mass outbreaks mainly affecting students have led to the closure of more than 20 schools stretching from the Guangxi Zhuang Autonomous Region in the south to Ningxia Hui Autonomous Region in the northwest, just one week after the start of the new school term.

    A Shanghai-made A/H1N1 vaccine will be evaluated by the State Food and Drug Administration on Thursday, its final hurdle before being officially licensed for production, officials from the Shanghai Institute of Biological Products said.

    The institute's vice director, Wang Menglian, said the vaccine is in line to be the third approved by the FDA. Sinovac Biotech Ltd. in Beijing and Hualan Biological Engineering Inc. in Henan, have already received licenses to produce A/H1N1 vaccine.

    The Chinese mainland had reported 4,415 cases of A/H1N1 flu, ofwhich 3,577 had recovered, the Health Ministry said Friday evening. No deat hs had been reported.

    Globally, the disease had killed about 2,000 people and infected more than 180,000 in more than 170 countries.

Special Report:  World Tackles A/H1N1 Flu