Two of the world’s leading HIV experts have suggested that we are approaching a usable HIV vaccine. There are currently three vaccines in clinical trials in humans. These vaccines are known as HVTN 702, Imbokodo and Mosaic.
Dr. Susan Buchbinder is the director of the Bridge HIV research program at the San Francisco Department of Public Health. She also chairs the Imbokodo and Mosaic tests.
She told NBC: “We have three vaccines that are currently being tested in efficacy trials and it takes a lot to be promising enough in the early stages of the trials to take you to an efficacy study.”
She called this moment, “perhaps one of the most optimistic moments we have been in.”
Imbokodo trials began in South Africa, where more than 50% of women between 18 and 25 years old lived with HIV, in 2017.
Mosaic, which is a form of vaccine very similar to Imbokodo, began last month. Both use a “mosaic” of immunogens to elicit an immune response to a variety of different strains of HIV. They require six injections in four separate sessions.
While both are being tested in South Africa, Mosaic will also be tested on 3,800 gay men and trans people at 57 sites in the United States, Latin America, and Europe.
The other vaccine, HVTN 702, was developed after the failure of an earlier vaccine, RV144. That vaccine only reduced HIV infection by 30%, which is not good enough to be used widely. Since the vaccine failed in the late 00s, researchers at the National Institute of Allergy and Infectious Diseases (NIAID) have been modifying it to be more effective.
The new vaccine is being tested in South Africa since 2016.
Dr. Anthony Fauci, director of NIAID, says that even a vaccine that has proven to be 50% effective would dramatically reduce infection rates in places like sub-Saharan Africa. The lower the number of people in a population that carry the virus, the less likely it is to be transmitted to other people.
Fauci says that if used in conjunction with PreP and Treatment as Prevention (having newly diagnosed people take medications quickly to make them undetectable), even a partially effective vaccine might be worth deploying sooner rather than later.
“If one or more of these vaccines look good, they are 50-60 percent effective, I think that will change the game to turn the epidemic around.”
The results of the HVTN 702 could reach the end of next year.
When new vaccines or medications are tested, the trial can be suspended early, that happens if the product being tested shows overwhelming evidence that it works, or if it shows no evidence that it works or even causes harm. So far, none of the trials have stopped. This suggests that vaccines are having an effect, but none is a resounding success.
However, Fauci believes that even a partially effective vaccine, when used in conjunction with other methods, can tip the balance against HIV.
In addition to PrEP, treatment as prevention and vaccine trials, the NIAID and the Bill and Melinda Gates Foundation announced in October their plans to invest at least $ 100 million each in the next four years to develop an affordable cure and gene-based for HIV.
Matthew Hodson, executive director of the NAM HIV information service, told Queerty: “This is an exciting time in vaccine development. None of these vaccines are expected to offer 100% protection, but they can offer 50% or more protection, which would be useful for communities with high HIV rates.
“We have seen that a combined approach to prevention, which includes the use of condoms, PrEP and testing people and suppressing viral infection (also known as ‘undetectable’) in treatment, reduces the new infections. Adding another powerful tool to our prevention kit could make a big difference. ”