They said China had learned from its mistakes with SARS and was working to control the AIDS virus, which has infected an estimated 650,000 Chinese.

"China was somewhat slow to respond but once they responded they did it in a big way," Roger Detels, an epidemiologist at the University of California, Los Angeles, who led the team, said in a telephone interview.

"And I think it is appropriate to praise them for responding vigorously."

Writing in the Lancet medical journal, Detels and colleagues singled out the government of President Hu Jintao for unusual praise. Hu, for example, publicly shook hands with AIDS patients, helping to battle the stigma, they pointed out.

"I think that was enormously important," Detels said.

Countries that have succeeded in battling AIDS, such as Uganda and Thailand, have all had major commitments from the top of the government, he said.

"The challenge of managing the severe acute respiratory syndrome (SARS) epidemic in 2003 is often credited with further motivating the government to take aggressive policy action on HIV-related issues," they wrote.

"SARS showed not only how infectious diseases could threaten economic and social stability but also the effect of China's policies on international health problems."

Detels and colleagues said China mistakenly tried to keep the AIDS virus out in the 1980s.

"These early policies did little to stop transmission of HIV; in fact, they probably promoted concealment of risk activities and made identification of HIV reservoirs more difficult," they wrote.

The government now provides free AIDS drugs to rural residents and city-dwellers without insurance. Other measures include:

-- Free voluntary counseling and testing

-- Free drugs to HIV-infected pregnant women to prevent mother-to-child transmission, and HIV testing of newborn babies

-- Free schooling for AIDS orphans

-- Care and economic assistance to the households of people living with HIV/AIDS.

"These bold programs have emerged from a process of gradual and prolonged dialogue and collaboration between officials at every level of government, researchers, service providers, policymakers and politicians, and have led to decisive action," concluded the researchers, who include Zunyou Wu of China's National Center for AIDS/STD Control and Prevention and Sheena Sullivan of Edith Cowan University, in Perth, Australia.

HIV infects 39 million people globally and experts fear the incurable disease will spread even farther if countries do not act to control it.