MEXICO CITY (Reuters) - More than 17 percent of HIV patients being treated for their infection in China developed resistance to available drugs by 2006 and 2007, according to a new nationwide survey.

A volunteer with HIV/AIDS makes AIDS symbols with red ribbons on the outskirts of the northeastern Indian city of Siliguri August 5, 2008. REUTERS/Rupak De Chowdhuri

With only seven of the more than 20 different HIV drugs available in China, the finding, announced by Chinese government researchers at an international AIDS conference in Mexico City, means these patients quickly end up with limited options. HIV infection is incurable but cocktails of the drugs can control it.

And the finding is surprising because the virus usually mutates into drug-resistant form only after people have been taking the drugs for a while. China began its national free HIV drugs program in 2003 and very few people had access to drugs before then.

Chinese government researchers said those who developed drug resistance tended to be from families with low and unstable incomes.

“When we first started, we didn’t have much experience and patients tended to be suspicious if these medications would work. So their adherence was not good and that resulted in higher rates of drug resistance,” said Liao Lingjie from the National Center for AIDS/STD Control and Prevention at the Chinese Center for Disease Control and Prevention.

The Chinese government estimated at the end of 2007 that about 700,000 people were infected with HIV, up from an earlier estimate of 650,000.

According to official Chinese media, about 20,000 Chinese were receiving free HIV drugs by the end of 2006. It is not clear how many people in China need to buy their own drugs.

The World Health Organization, however, estimated earlier that 122,000 people in China would have required HIV drugs by the end of 2004.

Liao said the survey covered 28 provinces.

She said in an interview that “17.6 percent of patients were found to be resistant to at least one drug,” but stressed that this has since improved. “People who began treatment later are responding better,” she said.

Liao said authorities are now following up on those patients who have become resistant to the available drugs and a small number of them have been put on a pilot trial.

“A small number of people are now trying out second-line drugs to see if the medication is suitable,” she said.

China has been battling an acknowledged rise in HIV infections, which are now mainly sexually transmitted. In the past, most infections were caused by intravenous drug use.

But the AIDS epidemic really took off in the 1990s in China’s central province of Henan because of unhygienic commercial blood donation schemes that resulted in entire villages becoming infected.

In recent years, China has given free medicines to many rural AIDS patients, as well as some economic help, and national leaders have held public meetings with patients to ease the stigma that many still suffer.

But patients and rights advocates complain that they are blocked from suing hospitals and officials they blame for helping spread HIV.