Gao Yaojie, a 77-year-old retired doctor who spends much of her time helping HIV/AIDS sufferers, said Henan officials had sent two people to Beijing from her former workplace to force her to go home.
"They came all the way to Beijing to catch me. I'm afraid to go back to my hotel," said Gao, who was staying with other AIDS prevention volunteers at a Beijing university.
Two cadres from Gao's old workplace, a hospital run by the Henan Chinese Medicine Institute, tried to get into the symposium on AIDS at Tsinghua University attended by Clinton Monday.
"It's exactly because it is such a high-profile event that they didn't want Dr. Gao to be there," said Hu Jia, a Beijing-based AIDS volunteer helping Gao.
Tsinghua University officials stopped the officials from entering.
Gao had to leave her home in Zhengzhou city, the capital of Henan, a day earlier than scheduled to dodge officials at the train station, who would have tried to prevent her from coming to Beijing, Hu said.
Clinton and Gao did not have a chance to meet at the symposium.
"It's regrettable. It would have been good if Clinton could have a chance to meet with the volunteer AIDS activists in China," Hu said.
Gao has received international awards for her work and has been one of the most vocal campaigners in publicizing the plight of AIDS sufferers in rural China, but continues to face intimidation from Henan authorities.
Up to a million poor farmers in Henan province are believed to have been infected with the HIV virus after selling blood from the mid-1980s to mid-1990s at unsafe blood collection stations.
China admits to having only 840,000 HIV/AIDS patients and that since 1985 around 150,000 have died. Independent health organizations, including Chinese non-government AIDS awareness groups, estimate there are many more.