TABLE 1.

Protective effectsa of high levels of antibodies to individual antigens

Antigen% of children with high-titer responseUnivariate analysisbAge-adjusted analysisbAge and schizont adjustedb
Risk ratio (95% CI)P valueRisk ratio (95% CI)P valueRisk ratio (95% CI)P value
AMA1_FVO490.45 (0.25-0.80)0.007*0.60 (0.33-1.08)0.0930.65 (0.36-1.21)0.178
AMA1_3D7510.40 (0.22-0.72)0.002*0.50 (0.28-0.90)0.021*0.54 (0.29-1.00)0.052
MSP-2_CH150/9540.32 (0.17-0.59)0.000*0.39 (0.21-0.70)0.002*0.41 (0.22-0.74)0.004*
MSP-2_Dd2540.28 (0.15-0.53)0.000*0.35 (0.18-0.65)0.001*0.36 (0.19-0.70)0.003*
MSP-3_K1390.39 (0.20-0.78)0.008*0.50 (0.26-0.95)0.037*0.52 (0.27-1.01)0.055
MSP-3_3D7400.58 (0.32-1.04)0.0720.67 (0.38-1.17)0.1660.70 (0.40-1.22)0.216
EBA-175_F2_CAMP340.72 (0.40-1.29)0.2741.05 (0.60-1.82)0.8581.25 (0.71-2.19)0.437
EBA-175_F2_3D7410.41 (0.21-0.79)0.008*0.53 (0.27-1.04)0.0670.57 (0.29-1.14)0.114
MSP-1_B2_3D7200.43 (0.12-1.12)0.0850.56 (0.20-1.50)0.2520.60 (0.22-1.64)0.328
MSP-1_B2_PaloAlto180.93 (0.47-1.83)0.8460.91 (0.48-1.71)0.7740.95 (0.50-1.81)0.895
MSP-1_B2_Wellcome190.33 (0.11-1.00)0.0510.50 (0.16-1.51)0.2220.54 (0.18-1.65)0.286
MSP-1_B2_MAD20230.48 (0.21-1.12)0.0920.73 (0.32-1.70)0.4780.76 (0.33-1.78)0.543
MSP-1_B2_RO33151.40 (0.77-2.53)0.2631.20 (0.74-1.93)0.4431.43 (0.86-2.38)0.162
MSP-119361.44 (0.87-2.38)0.1481.14 (0.74-1.76)0.5441.59 (0.93-2.74)0.089
  • a Risk of developing clinical malaria associated with high titers compared to low/undetectable titers of antibodies to individual antigens in a subset of the Chonyi cohort (n = 119). Antigens are designated by their locus name and P. falciparum strain ([locus]_[strain]).

  • b Risk ratios (with 95% confidence intervals [CI]) are presented for univariate and multivariate analyses (adjusted initially for age and subsequently for both age and reactivity to P. falciparum parasite schizont extract as a proxy for exposure). *, P < 0.05.