The results of two of these efficacy trials (STEP and Phambili trials) employing adenovirus serotype 5 (Ad5)-based vaccine with inserted gag-pol-nef genes of HIV-1 clade B, were deeply disappointing, as the vaccination not only failed to reduce the viral load after HIV-1 infection, but the incidence of HIV-1 infection in the STEP trial was higher among vaccinated individuals than in placebo-treated subjects [10]–[12]. The gene discussed is S100B; the disease is HIV-1 infection.