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.
In the 35 years since the HIV epidemic began, just four vaccines have been tested on humans, with the best only lowering infection rates by 31 per cent, leading to trials being discontinued.
But in what was described as ‘promising’ and ‘an important milestone’, an international team of scientists 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 dubbed “Imbokodo,” the Zulu word for rock, to represent the strength of women and their importance in the community.
“This study demonstrates that the vaccine candidate induced robust immune responses in humans and monkeys with 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.
“We eagerly await the results of the phase 2b Imbokodo’, which will determine whether or not this vaccine will protect humans against acquiring HIV.”
According to the Terence Higgins Trust there are around 89,400 people living with HIV in Britain, and around 10,400 do not know they are infected.
London continues to have the highest HIV prevalence in the country with 40 per cent of those diagnosed living in the capital. Nearly one in 50 people living in the borough of Lambeth has the disease.
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.
Worldwide the picture is very different with an estimated 37 million carrying HIV and only 50% getting the drugs they require to keep full blown AIDS at bay.
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 USA 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 anti-HIV 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.
Dr Michael Brady, Medical Director at Terrence Higgins Trust, said: ‘“It’s still very early days for this HIV vaccine, but the signs are promising and very few trials progress to testing in humans who are at risk of HIV.
“However, it’s important to be cautious and be clear that there’s a lot of work to do before an effective HIV vaccine is readily available.
“We welcome research into vaccines and cures as part of our response to the global pandemic but, for now, it is important to remember that we already have a range of highly effective tools for preventing HIV, including condoms, regular testing and Pre-Exposure Prophylaxis.”
The study results were published in The Lancet. The trial is sponsored by Janssen Vaccines & Prevention, part of Johnson & Johnson.
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