China has slashed AIDS mortality by nearly two-thirds since it began distributing free antiretroviral drugs in 2002, Chinese government scientists are reporting.

About 63 percent of all those needing AIDS drugs are getting them, up from virtually zero in 2002. That has caused a 64 percent drop in mortality in “person-years,” as China measures it, an estimate of how long someone would have lived without the disease.

AIDS mortality dropped to 14.2 per 100 person-years in 2009, from 39.3 in 2002.

The study, led by China’s national center for control and prevention of AIDS and other sexually transmitted diseases, was published online on Wednesday by Lancet Infectious Diseases.

China’s success in such a short time “is a testimony to the young midlevel scientists who convinced the leadership that this was the right thing to do,” said Dr. Myron Cohen, an AIDS specialist from the University of North Carolina who has lived in China and helped it battle the epidemic.

A different report, released Wednesday by the International Labor Organization of the United Nations, criticized China’s health-care system, saying that people infected with H.I.V., the virus that causes AIDS, were frequently turned away by hospitals.

The report, based on interviews with patients, health care workers and hospital managers, says patients are sent by general hospitals to infectious-disease hospitals. But they often refuse to perform surgery, for example, for fear that paying patients will avoid the hospital if word spreads that it operates on AIDS patients. China’s national center for AIDS control, a co-author of the report, agreed that hospital discrimination was a problem.

The number of infected people in China — 740,000, according to estimates by the government and U.N.AIDS — is large by comparison with most countries, but small in a population of 1.3 billion. Of those, 323,252 have been tested and 82,540 are being treated.

If the total caseload estimate is correct, China has tested nearly half its infected people. By comparison, the United States estimates that 80 percent of its 1.1 million infected people have been tested.

China now begins treating when a patient’s CD4 cell count, a measure of immune system strength, drops below 350 per cubic millimeter.

It is now debating whether to start treatment as soon as a patient tests positive for H.I.V., Dr. Cohen said. A study released last week showed that this strategy, known as “treatment as prevention,” could reduce the risk of new infections by 96 percent by protecting an infected person’s sexual partners.

China’s biggest treatment success was among former plasma sellers. In the 1990s, tens of thousands of poor farmers sold plasma to commercial “bloodhead” operations. Their blood was mixed, the plasma skimmed off, and the mixed red cells were reinfused back into the sellers.

Reinfusion is routine in plasma donation, but the process allowed H.I.V. to spread rapidly among donors. Soon, in some rural villages, 50 percent of adults were infected.

Many of the early victims died before 2002, but among the survivors, according to the study, 80 percent are now getting antiretroviral drugs. By contrast, the figure for those infected through sex is about 60 percent; for those infected by injecting drugs, it is about 40 percent.

Drug injection is most common in the southern and western regions bordering Myanmar and Afghanistan, both of which grow opium. China now offers free needles and methadone to addicts, which draws many in to be tested for AIDS.

Infection through sex is most common among gay men and customers of prostitutes. Many gay people still keep their sexual orientation hidden. Also, visiting prostitutes is common among migrant laborers living illegally in crowded city apartments.

In 2010, China estimated that 85 percent of female prostitutes used condoms. Other studies suggest that fewer than 1 percent are infected, but high-risk sex is common enough to let infections continue.

The International Labor Organization report says the health care system still fails homosexuals, drug users, prostitutes and ethnic minorities because of lingering prejudices against them and against AIDS in general. And it is not reaching many elderly patients and migrants.

Still, China is no longer in deep denial about its epidemic, as it was until a decade ago.

In 1990, the education ministry said sexual morality and self-discipline would keep AIDS out. Imports of blood products were banned and foreigners were required to take blood tests. The police barred foreigners from dance halls and took other steps to prevent sex with outsiders. In 1999, China’s first condom ad was banned as offensive two days after it was released. 

In 2001, there was an official change of heart. The government publicly admitted that 500,000 to one million people were infected and asked for outside help. Condoms were reclassified as “safety devices.” At the same time, China said that if Western companies did not lower their prices, it would make antiretroviral drugs itself.

In 2002, China applied for $90 million from the Global Fund to Fight AIDS, Tuberculosis and Malaria to begin its free drugs program. In return, it was forced to free an AIDS activist who had been imprisoned after posting details of unsanitary sales of blood in Henan Province. AIDS activists are still sometimes detained.