Impact of behavioral risk score on association between FcγRIIIa genotype and HIV infection rate in vaccinated subjects. (A) Among rgp120-vaccinated subjects with low behavioral risk scores (risk score = 0), those with the FcγRIIIa VV genotype acquired HIV infection at a greater rate than those with the FV (hazard rate = 4.12; P = .002), FF (hazard ratio = 2.97; P = .019), and combined FF/FV genotypes (hazard rate = 3.52; P = .002). (B) Among vaccinees with high behavioral risk scores (risk score ≥ 1), there is no significant association between FcγRIIIa genotype and infection rate; there is, however, a trend toward a greater infection rate for the FF genotype compared with the FV genotype (hazard ratio = 1.31; P = .09). Risk scores were assigned at enrollment in the Vax004 trial.