Major breakthrough in search for HIV vaccine that could save millions of lives

A vaccine for HIV is a massive step closer following trials in the US in which a test jab triggered antibodies capable of neutralising the virus.

The immune response happened within weeks of a two-part vaccine being administered, raising hopes that a simple and commercial prevention is possible.

HIV, or human immunodeficiency virus, damages cells in the immune system, weakening the body’s ability to fight normal infections and disease. It can now be well managed using medication, but is still a leading cause of death in areas without adequate treatment.

A vaccine could save millions of lives worldwide.

While the test jab only triggered low levels of the antibodies, they were a type capable of fighting a range of HIV strains.

Senior author Dr Barton Haynes, from the Duke Human Vaccine Institute (DHVI), said: ‘This work is a major step forward as it shows the feasibility of inducing antibodies with immunisations that neutralise the most difficult strains of HIV.

‘Our next steps are to induce more potent neutralising antibodies against other sites on HIV to prevent virus escape. We are not there yet, but the way forward is now much clearer.’

The antibodies target an area on the HIV pathogen’s outer layer called the membrane proximal external region (MPER), helping to block infection by the virus.

The trial involved 20 healthy, HIV-negative participants. Fifteen received two doses, and five received three.

After just two injections, participants showed strong immune activation.

Researchers initially planned to test four doses, but the trial was halted after one participant experienced a non-life-threatening allergic reaction, thought to be from an additive.

Lead author Dr Wilton Williams, also from Duke, said: ‘To get a broadly neutralising antibody, a series of events needs to happen, and it typically takes several years post-infection.

‘The challenge has always been to recreate the necessary events in a shorter space of time using a vaccine. It was very exciting to see that, with this vaccine molecule, we could actually get neutralising antibodies to emerge within weeks.’

To create the most robust vaccine, the team said it will need to target more regions of the envelope, and will likely have to attack at least three different parts of the virus.

‘Ultimately, we will need to hit all the sites on the envelope that are vulnerable so that the virus cannot escape,’ said Dr Haynes. ‘But this study demonstrates that broadly neutralising antibodies can indeed be induced in humans by vaccination.’

The study is published in the journal Cell.