Because vaccines are usually given to healthy people, there are strict standards to which vaccine development must adhere and higher thresholds for measuring safety. Before a vaccine is allowed to be tested in humans, it has to show potential for triggering an immune response; this is done in pre-clinical testing in animals. Human (clinical) testing then proceeds in three stages to ensure that the vaccine is safe and effective:
Imbokodo and Mosaico use slightly different versions of “mosaic” vaccines that incorporate genetic material from a wide variety of HIV clades. Imbokodo participants receive Ad26.Mos4 vector as well as a clade C envelope protein. Mosaico participants receive the same regimen augmented by an additional “mosaic” envelope protein to broaden immune responses.
Janssen Vaccines & Prevention B.V., part of the pharmaceutical company, Johnson & Johnson, sponsor Imbokodo and Mosaico in partnership with the HIV Vaccine Trials Network (HVTN) and the US National Institute of Allergy and Infectious Diseases (NIAID). Earlier clinical studies were also supported by the Bill & Melinda Gates Foundation.
The results of Imbokodo are expected in late 2022, with Mosaico concluding a year later.