国际英语新闻:First HIV vaccine efficacy study in years begins in South Africa: U.S. agency

WASHINGTON, Nov. 28 (Xinhua) -- The first HIV vaccine efficacy study in seven years has begun in South Africa to test whether an modified vaccine candidate can provide effective protection against the AIDS virus, the U.S. National Institutes of Health said Monday.

The study, called HVTN 702, aims to enroll 5,400 sexually active men and women aged 18 to 35 years, making it the largest and most advanced HIV vaccine clinical trial to take place in South Africa, where more than 1,000 people become infected with HIV every day.

"If deployed alongside our current armory of proven HIV prevention tools, a safe and effective vaccine could be the final nail in the coffin for HIV," Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health and a co-funder of the trial, said in a statement.

"Even a moderately effective vaccine would significantly decrease the burden of HIV disease over time in countries and populations with high rates of HIV infection, such as South Africa."

The experimental vaccine regimen being tested in HVTN 702 is based on the one investigated in the RV144 clinical trial in Thailand that was found to be 31.2 percent effective at preventing HIV infection over the 3.5-year follow-up after vaccination.

The new vaccine regimen has been adapted to the HIV subtype that predominates in southern Africa and a smaller initial trial involving 252 people has found that it was safe for the study participants and induced comparable immune responses to those reported in RV144.

The new trial, to be conducted at 15 sites across South Africa, aims to test whether it will provide greater and more sustained protection than the RV144 regimen.

Volunteers will been randomly assigned to receive either the investigational vaccine regimen or a placebo. All participants will receive a total of five injections over one year, and results are expected in late 2020.

"HIV has taken a devastating toll in South Africa, but now we begin a scientific exploration that could hold great promise for our country," said HVTN 702 Protocol Chair Glenda Gray, president and chief executive officer of the South African Medical Research Council.

"If an HIV vaccine were found to work in South Africa, it could dramatically alter the course of the pandemic."