HIV Vaccine Could Potentially Provide Immunity

Modesto Morganelli
Luglio 9, 2018

In a similarly designed study, Barouch and colleagues tested the same vaccine for its ability to protect rhesus monkeys challenged with an HIV-like virus from infection.

The experimental HIV-1 vaccine is one of five that have progressed to tests of effectiveness in humans.

Only four vaccine concepts have made it to testing in humans, and only one provided any evidence of protection in an efficacy trial, but the effect was considered too low to make it available for use.

Shown to be safe in humans, the candidate vaccine has now advanced to the next phase of the pre-approval trial process, and will be tested in 2,600 women in southern Africa to see whether it prevents HIV infection. "Obviously, the search for an HIV vaccine is very elusive", said Dr. Carlos del Rio, who was not involved with the study but has done similar research as the co-principal investigator of the Emory-CDC HIV Clinical Trials Unit.

Unlike past efforts, which only focused on specific HIV strains, this vaccine is a "mosaic" that includes pieces of multiple strains in a bid to create a more universal drug.

It was found that the mosaic Ad26/Ad26 plus high-dose gp140 boost vaccine was the most immunogenic in humans and these results were comparable in the parallel monkey study where 67% of the 72 monkeys evaluated were protected against disease with this combination vaccine.

The vaccine could have the potential to protect people around the world from the threat of the virus.

About nine years ago, another HIV vaccine, RV144, also showed positive results in initial experiments carried out on 16,000 volunteers in Thailand.

More tests will now need to take place to determine if the immune response produced can prevent HIV infection in people. At present around 37 million individuals are living with HIV/AIDS with 1.8 million new infections and 1 million deaths annually says the World Health Organization.

But despite advances in treatment for HIV, a cure or vaccine against the virus has never been found. "We have to acknowledge that developing an HIV vaccine is an unprecedented challenge, and we will not know for sure whether this vaccine will protect humans".

A new HIV vaccine is inspiring "cautious" hope in scientists after it passed human trials with "promising" results. The participants were randomly assigned one of seven combinations of a vaccine, while one group was given a placebo. Scientists must await the results of this trial find out whether the vaccine cannot only provoke an immune response, but actively protect against HIV.

An accompanying editorial by George N. Pavlakis, MD, and Barbara K. Felber, PhD, both of the National Cancer Institute in Frederick, Maryland, discussed this approach, stating that it "defines an additional path for exploring the development of an effective HIV vaccine".

The participants, from the US, Rwanda, Uganda, South Africa, and Thailand, received four vaccinations over the course of 48 weeks. It's unclear whether it would provide protection in humans.

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