Long-awaited AIDS vaccine trials to get under way

An AIDS vaccine trial that will infuse people with antibodies known to neutralise 85 percent of HIV strains will begin in southern Africa, the US and South America within months.

Announcing the trial, SA Medical Research Council president, Dr Glenda Gray, said we are entering the most exciting period - a golden era of HIV-prevention research - that has taken us 30 years to get to. The vaccine will inject people with "broadly neutralising antibodies" (bNA) that have been isolated by the US National Institutes of Health, based on decades of research on HIV-infected people who have been able to hold the virus in check.  Because HIV mutates so fast, scientists have pinned their hopes on bNAs that are able to neutralise a large number of strains at a time, rather than one or two strains. The vaccine will be tested on gay men in the US and South America from next month and women in sub-Saharan Africa from January.

At least seven South African trial sites will be involved, and HIV-negative women aged between 18 and 30 will be recruited. The trial participants - about 3 900 globally - will each get a half-hour intravenous infusion via a drip with the special antibodies every two months for 20 months. Results will become available in late 2018. Alongside the neutralising antibody trial, South Africans are testing another vaccine that aims to stimulate the body to fight HIV.

This trial is a continuation of the 2009 Thailand trial (called RV144), the only vaccine ever to have elicited any immune response in trialists. After a year, it had protected 60 percent of those involved against HIV, but the protective effect had halved by 3,5 years. The Thai vaccine has been re-engineered to use the type of HIV most common in southern Africa (Clade C), and this has been tested on South Africans.

A large-scale trial of the vaccine is due to start next year. Trial participants will get an initial vaccine, then a vaccine boost after 12 months to see whether this can maintain the body's immune response. Gray said it might mean that people need to get a yearly booster shot, adding that the efficacy of the measles vaccine also waned over time.

Health-e News Service, 21 October 2015