South Africa is set to begin trials later this year for a vaccine against the Human Immunodeficiency Virus (HIV), having met the criteria needed to prove it could help fight the epidemic in Africa. The HIV virus, which is still prevalent across the continent, accounted for two thirds of 2.1 million reported infections in 2015.
Set to begin in November, this trial comes on the back of a preliminary trial that took place in South Africa in 2015 to test the safety and strength of immunity the vaccine could provide, before subjecting affected populations to larger-scale testing. The results of the small trial, known as HVTN100, were presented on Tuesday at the 21st International AIDS Conference in Durban, South Africa.
The precautionary trials, which involved the injecting of 250 healthy volunteers with either the vaccine or a placebo, were deemed to have met the criteria set for effectiveness. “Four criteria were set as measures of its likely effectiveness, including the level of T-cell and antibody response to fight the virus if it were to infect. It gives the tick on all four, it does look promising and it should launch,” said Gail Bekker, Deputy Director of the Desmond Tutu HIV Centre in Cape Town, South Africa and president-elect of the International AIDS Society, who is leading the vaccine trials. “We wanted to see a particular immune picture that would suggest that a big efficacy trial would be likely to yield results,” she said.
The vaccine first showed a potential to protect against HIV, in a seminal trial in Thailand in 2009, with 31 percent protection against the virus. “The obvious question is: Can we now replicate those results and can we improve upon them with greater breadth, depth and potency?” asked Anthony Fauci, Director of the National Institutes of Allergy and Infectious Disease, whose organisation sponsors the study. The vaccine has since been improved for use in higher risk populations in sub-Saharan Africa where different sub types of the virus also exist. ‘A component known as adjuvant was added to stimulate stronger immunity,’ explained Gail Bekker.
Given the success of the preliminary study a larger-scale trial of the vaccine is now set to begin in November 2016, spanning three years with 5,400 people across four sites in South Africa. The vaccine trials in Thailand showed a 60 percent protection against HIV in the first year , a 31 percent protection after the second year, and this study hopes that with the addition of new components to the vaccines the protection against HIV can be retained at 60 percent for a longer period of time.
The success of the upcoming trials is unlikely to result in its licensing but will provide the evidence needed by manufacturers and vaccine regulators to take it further. A cure for HIV has been elusive so far, despite the extensive resources devoted to it; a vaccine would be an important step towards combating the epidemic on the continent. The release of the vaccine will not provide enough protection on its own but will need to be used in combination with other preventive apparatus already in place.