The genetic diversity of the HIV virus is greater than any other pathogen, and constructing an effective vaccine is vital, despite its scientific challenges, says Professor Glenda Gray.
Gray, president of the South African Medical Research Council (SAMRC) and chief executive, said they had a rich scientific portfolio in approaches, but the hurdle lay in putting these difference approaches into a coherent vaccine regimen.
She was speaking at the 2023 11th Aids conference last week, in Durban, under the theme “Act, Connect and End the Epidemic”, where she said the goal was to prevent acquisition or cure early established disease, a much higher bar than traditional vaccines like Covid-19, reports IOL.
“Many parts of the HIV trimer create diversionary antibodies and we don’t have a systematic approach to define these and cut them out. There are also many fewer trimers on the surface than most viruses and neutralising antibodies cannot cross-link,” she said, adding that there were no human cures for HIV, hence no immunological models to mimic.
“However, the study of Antibody-Mediated Prevention (AMP) demonstrates that broadly neutralising antibodies are capable of preventing HIV acquisition and provide the future roadmap for vaccine development.”
The study also demonstrated that they need to make broadly neutralising antibodies (bNAbs) to more than one site, she said. The bNAbs are a type of antibody that can recognise and block the entry of a broad range of different strains of HIV into healthy cells.
“Vaccine approaches need to shift to eliciting antibodies to known conformational structures that elicit such antibodies,” said Gray.
Talking about pre-exposure prophylaxis (PrEP), Professor Sinead Delany-Moretlwe, from the Wits Reproductive Health HIV Institute, said people who used PrEP discontinued after six months. She said when it was introduced 2.2m people used it around the world.
“After six months, 41% of them discontinued taking the pill. They were tired of taking it every day – 31% of those people are young females,” she said.
Delany-Moretlwe added that there was a need for a range of options for prevention that could provide a choice and increase HIV prevention coverage across the life course.
She also raised concerns about the costs and accessibility of PrEP, saying prices might limit access, despite effectiveness.
IOL article – Medical personnel insist on HIV vaccine (Open access)
See more from MedicalBrief archives:
Back to drawing board for HIV vaccine after latest setback
Johnson & Johnson and global partners halt HIV vaccine clinical trial
New HIV vaccine test awaits SAPRA green light
SA’s HIV epidemic still requires an emergency response