Experts working on vaccine to fight AIDS in China

By Tan Ee Lyn

HONG KONG (Reuters) - Scientists in Hong Kong and China are working on an AIDS vaccine to protect against three variants of HIV sweeping across south and west China, Hong Kong and Taiwan.

Chen Zhiwei, director of the new AIDS Institute in Hong Kong, said scientists have been using gene sequencing to track how HIV viruses in China are evolving, and their geographical spread.

Two closely-related HIV variants had spread through intravenous drug users (IDUs) from southwestern Yunnan province; one to as far as Xinjiang in the northwest, and the second to Guangdong in the south.

The third variant is in Yunnan and southern Guangxi province, which Chen said is passed mainly through heterosexual sex.

Chen, who worked alongside famous HIV/AIDS scientist David Ho in the U.S. before heading the Hong Kong institute, said collaborating scientists in the U.S. and China have designed a vaccine based on the two HIV variants spreading among IDUs and they hope to test it in animals by the end of this year.

"If you want to make a vaccine, it is better to have a local strain as a target to work on," Chen said in an interview with Reuters.

Asked if the experimental vaccine may confer protection against the third variant that is transmitted chiefly through sex, Chen said: "That's what we want to know. There is about 60-70 percent identity between the subtypes. If viruses are very closely related, chances of cross protection are better."

The HIV variants circulating in south and west China are very similar to those found in Myanmar, Vietnam, Cambodia, Thailand and India, as well as in Taiwan and Hong Kong, he said.