VACCINES TO PREVENT HIV INFECTION
Despite the many efforts to develop a safe and effective vaccine against HIV infection, the results to date have been negative or controversial at best. Among the reasons for this state of affairs have been the enormous genetic diversity of the virus and the unique features of the HIV envelope protein. One thing we have learned from studies of HIV pathogenesis, however, has been that a vaccine that induces a strong and specific T-cell immune response in the absence of broadly neutralizing antibodies may blunt initial viremia, even if the infection is not completely prevented. Moreover, they may prevent the mass destruction of CD4 T cells, thereby helping to control the infection and prolong disease-free survival.