‘Promising’ drug tests raise hopes of HIV vaccine

International team of scientists says trial boosted immune systems of 400 healthy adults

A VACCINE against HIV is on the horizon after scientists showed a new drug triggered a protective immune response in humans and stopped two thirds of monkeys becoming infected when exposed to the virus. In the 35 years since the HIV epidemic began, just four HIV vaccines have been tested on humans, with the best only lowering infection rates by 31per cent, leading to trials being discontinued.

But in what was described as “promising” and “an important milestone”, an international team of scientists has showed that the new vaccine boosted the immune systems of nearly 400 healthy adults.

And when vaccinated rhesus monkeys were exposed to the disease six times, only one third became infected.

Now scientists from institutions including Harvard, MIT and the National Institutes of Health have begun testing the vaccine on 2,600 women who are at risk of HIV in southern Africa, and hope to have results by 2021.

The trial has been nicknamed “Imbokodo,” the Zulu word for rock, to represent the strength of women and their importance in the community.

“These results represent an important milestone,” said Prof Dan Barouch, Professor of Medicine at Harvard Medical School, Boston, and Beth Israel Medical Center, who led the study, which was published in The Lancet.

“This study demonstrates that the vaccine candidate induced robust immune responses in humans and monkeys and also provided 67 per cent protection against viral challenge in monkeys. These results should be interpreted cautiously.

“The challenges in the development of an HIV vaccine are unprecedented, and the ability to induce Hiv-specific immune responses does not necessarily indicate that a vaccine will protect humans from HIV infection.”

According to the Terrence Higgins Trust there are around 89,400 people living with HIV in Britain, and around 10,400 do not know they are infected. However improvement in drugs means the disease is now manageable, and the overall mortality rate for people aged 15 to 59 who are diagnosed early is now equal to that of the general population.

For the latest trial, scientists recruited 393 healthy adults between the age of 18 and 50 from clinics in east Africa, South Africa, Thailand and the United States between February 2015 and October 2015.

Volunteers were randomly assigned to receive either one of seven vaccine combinations or a placebo, and were given four vaccinations over the course of 48 weeks.

The new drug is made from several different HIV viruses and so could act as a universal vaccine throughout the world, experts hope.

Previous vaccine candidates have typically been limited to specific regions of the world.

Results showed that all vaccines tested were capable of generating antihiv immune responses in healthy individuals and were well tolerated.

In a parallel study, the researchers infected 72 rhesus monkeys with SHIV – a virus similar to HIV that infects monkeys – which resulted in complete protection in two thirds of the vaccinated animals.