The development of a vaccine to prevent HIV infection is a global health priority. To date, four vaccine strategies have been assessed for possible efficacy and only one has shown modest and short-lived efficacy. A significant challenge is how to elicit robust and durable anti-HIV-1 immune response.
To assess a novel HIV vaccine platform, researchers randomly assigned healthy adults without HIV infection to one of two interventions: a vaccine consisting of adenovirus serotype 26 with an HIV-1 envelope A insert (Ad26) or adenovirus serotype 35 with an HIV-1 envelope A insert (Ad35). Both were administered at a dose of 5 x 1010 viral particles in homologous and heterologous combinations.
The researchers found that all vaccine regimens were well-tolerated and elicited both humoral and cellular immune responses. Both heterologous and homologous regimens significantly increased humoral Env responses, suggesting that a vaccine that inserts an HIV-1 envelope protein into a common adenovirus is a promising vaccine strategy for HIV-1 prevention.