Considerable HIV-1 vaccine development efforts have been deployed over the past decade. Put into perspective, the results from efficacy trials and the identification of correlates of risk have opened large and unforeseen avenues for vaccine development.
The Thai efficacy trial, RV144, provided the first evidence that HIV-1 vaccine protection against HIV-1 acquisition could be achieved. The correlate of risk analysis showed that IgG antibodies against the gp120 V2 loop inversely correlated with a decreased risk of infection, whereas Env-specific IgA directly correlated with risk. Further clinical trials will focus on testing new envelope subunit proteins formulated with adjuvants capable of inducing higher and more durable functional antibody responses (both binding and broadly neutralizing antibodies). Moreover, vector-based vaccine regimens that can induce cell-mediated immune responses in addition to humoral responses remain a priority.
Future efficacy trials will focus on prevention of HIV-1 transmission in heterosexual population in Africa and MSM in Asia. The recent successes leading to novel directions in HIV-1 vaccine development are a result of collaboration and commitment among vaccine manufacturers, funders, scientists and civil society stakeholders. Sustained and broad collaborative efforts are required to advance new vaccine strategies for higher levels of efficacy.
aU.S. Military HIV Research Program (MHRP), Bethesda, Maryland
bDuke Human Vaccine Institute, Department of Surgery
cDuke Human Vaccine Institute, Department of Immunology
dDuke Human Vaccine Institute, Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
eBill & Melinda Gates Foundation, Seattle, Washington, USA
Correspondence to Jean-Louis Excler, MD, U.S. Military HIV Research Program (MHRP), 6720-A Rockledge Drive, Suite 400, Bethesda, MD 20817, USA. Tel: +63 947 893 7459; e-mail: firstname.lastname@example.org