mRNA HIV vaccine trial to start

Moderna has started a trial for its HIV vaccine, based on mRNA technology.

After its successful development of the COVID-19 vaccine last year, the US pharmaceutical and biotech company will use mRNA technology in two new HIV vaccines. A series of these will be used alongside some HIV vaccines already developed using more traditional vaccine technology. Together they are designed to trigger a specific type of immune cell called B-cells, to create antibodies that are known to 'neutralise' HIV. These are the same type of B-cell that is triggered by current HIV treatment and PrEP, which is given prophylactically to people at greater risk of exposure to HIV or those who know they have been exposed to the virus.

'Moderna are testing a complicated concept which starts the immune response against HIV,' Professor Robin Shattock, an immunologist at Imperial College London, who is not involved in the trial told The Independent, 'It gets you to first base but it's not a home run. Essentially we recognise that you need a series of vaccines to induce a response that gives you the breadth needed to neutralise HIV.'

HIV is a virus that is blood-borne or sexually transmitted and affects a person's immune system making them less able to fight off infections, and more likely to develop certain cancers. Upon entering human cells it mutates rapidly which makes it difficult for the immune system to learn how to attack it.

According to the US National Institutes of Health's clinical trials registry, 56 HIV-negative people between the ages of 18 and 50 have been recruited into the phase 1 trial which will test the overall safety of the vaccine, and see whether or not it creates an immunological response. There will be four groups on the first phase of the trial with two receiving a mix of the mRNA vaccine versions, and two receiving one or the other. The trial is not blind and participants will know which group they are in.

The two mRNA vaccines being trialled will eventually be used alongside a vaccine developed by the International AIDS Vaccine Initiative and Scripps Research. Earlier this year results from a trial of this vaccine showed 97 percent of participants who received the vaccine developed B cell stimulation, but not enough immune response. It is hoped the two Moderna mRNA HIV vaccines have the potential to prime a specific type of B-cell that can develop into cells that create HIV neutralising antibodies and the other vaccine will stimulate them to do so.

The study is expected to run until May 2023, with the first phase lasting around ten months.