Table 5.
Factors associated with risk of clinical malaria in univariate logistic regression models, showing odds ratios (OR) and 95% confidence intervals (CI).
| Antibody | Antibody levels | Age cohort | Sex | Site | WAZ | HAZ | Hb | Exposure index | Maternal antibodies | Prior episode† | Seasonǂ | Vaccine | IgG at M0 | IgM at M0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | |
| All participants together | ||||||||||||||
| IgG | 0.83 (0.55;1.24) 0.74 | 0.74 (0.38;1.42) 1 | 1.24 (0.7;2.19) 1 | 0.1 (0.05;0.19) <0.001 | 0.73 (0.55;0.95) 0.059 | 0.75 (0.57;0.96) 0.1 | 0.91 (0.74;1.11) 1 | 1.18 (1.09;1.28) <0.001 | 1.39 (1.22;1.61) <0.001 | 4.55 (1.69;14.5) 0.01 | 0.66 (0.17;2.26) 1 | 0.64 (0.35;1.16) 0.7 | 0.7 (0.38;1.28) 1 | 0.8 (0.56;1.13) 1 |
| IgG1 | 0.74 (0.49;1.1) 0.41 | 0.78 (0.43;1.43) 1 | 1.26 (0.71;2.23) 1 | 0.1 (0.05;0.19) <0.001 | 0.73 (0.56;0.95) 0.059 | 0.74 (0.57;0.96) 0.1 | 0.9 (0.73;1.11) 1 | 1.17 (1.08;1.27) <0.001 | 1.39 (1.22;1.6) <0.001 | 4.38 (1.62; 13.95) 0.01 | 0.68 (0.17;2.36) 1 | 0.6 (0.33;1.1) 0.61 | 0.8 (0.49;1.29) 1 | 0.83 (0.6;1.14) 1 |
| IgG2 | 1.01 (0.65;1.57) 0.95 | 0.79 (0.42;1.48) 1 | 1.48 (0.82;2.7) 1 | 0.1 (0.05;0.2) <0.001 | 0.7 (0.52;0.92) 0.047 | 0.73 (0.55;0.94) 0.09 | 0.89 (0.72;1.09) 1 | 1.16 (1.07;1.26) <0.001 | 1.39 (1.22;1.61) <0.001 | 3.8 (1.38;12.25) 0.02 | 0.49 (0.1;1.82) 1 | 0.66 (0.35;1.23) 0.7 | 0.71 (0.39;1.26) 1 | 0.84 (0.6;1.16) 1 |
| IgG3 | 0.02 (0;0.18) <0.001 | 1.34 (0.69;2.65) 1 | 1.24 (0.69;2.24) 1 | 0.12 (0.06;0.23) <0.001 | 0.71 (0.52;0.93) 0.059 | 0.76 (0.58;0.99) 0.1 | 0.87 (0.7;1.08) 1 | 1.18 (1.09; 1.28) <0.001 | 1.34 (1.18;1.55) <0.001 | 3.97 (1.44;13.02) 0.02 | 0.57 (0.14;2) 1 | 0.64 (0.34;1.19) 0.7 | 0.87 (0.54;1.4) 1 | 1.03 (0.73;1.45) 1 |
| IgG4 | 0.02 (0;0.2) 0.001 | 1.21 (0.63;2.36) 1 | 1.18 (0.66;2.11) 1 | 0.11 (0.06;0.22) <0.001 | 0.72 (0.54;0.95) 0.059 | 0.76 (0.58;0.98) 0.1 | 0.87 (0.7;1.07) 1 | 1.17 (1.09;1.28) <0.001 | 1.35 (1.18;1.56) <0.001 | 3.99 (1.44;13.08) 0.02 | 0.53 (0.13;1.84) 1 | 0.64 (0.34;1.18) 0.7 | 0.82 (0.52;1.3) 1 | 1 (0.71;1.4) 1 |
| IgM | 0.43 (0.26;0.68) 0.001 | 1.87 (0.86;4.23) 0.7 | 1.07 (0.59;1.93) 1 | 0.11 (0.05;0.21) <0.001 | 0.65 (0.48;0.86) 0.01 | 0.75 (0.57;0.98) 0.1 | 0.84 (0.67;1.04) 0.6 | 1.27 (1.16;1.4) <0.001 | 1.32 (1.15;1.53) <0.001 | 4.43 (1.6;14.39) 0.01 | 0.47 (0.12;1.68) 1 | 0.65 (0.35;1.2) 0.7 | 0.82 (0.51;1.29) 1 | 1.44 (0.91;2.33) 0.7 |
| Antibody levels | Sex | Site | WAZ | HAZ | Hb | Exposure to malaria | Maternal antibodies | Prior episode† | Seasonǂ | vaccine | IgG at M0 | IgM at M0 | ||
| OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | ||
| Infants | ||||||||||||||
| IgG | 1.04 (0.43;2.51) 1 | 1.31 (0.61;2.81) 1 | 0.13 (0.05;0.32) <0.001 | 0.84 (0.58;1.22) 1 | 0.72 (0.5;1) 0.28 | 1.12 (0.81;1.58) 1 | 1.16 (1.03;1.33) 0.07 | 1.35 (1.16;1.61) <0.001 | 4.61 (1.09;31.58) 0.22 | 0.53 (0.13;1.91) 1 | 0.89 (0.4;1.98) 1 | 0.98 (0.38;2.53) 1 | 0.69 (0.36;1.26) 1 | |
| IgG1 | 0.81 (0.41;1.52) 1 | 1.29 (0.61;2.77) 1 | 0.14 (0.06;0.35) <0.001 | 0.84 (0.57;1.21) 1 | 0.72 (0.5;1) 0.28 | 1.11 (0.79;1.57) 1 | 1.16 (1.03; 1.33) 0.07 | 1.35 (1.15;1.61) <0.001 | 4.45 (1.04;30.73) 0.22 | 0.58 (0.14;2.08) 1 | 0.86 (0.38;1.92) 1 | 0.99 (0.47;2.1) 1 | 0.68 (0.36;1.26) 1 | |
| IgG2 | 1.65 (0.68;4.17) 1 | 1.83 (0.82;4.15) 0.83 | 0.15 (0.06;0.38) <0.001 | 0.77 (0.52;1.13) 0.92 | 0.71 (0.49;1) 0.28 | 1.06 (0.76;1.51) 1 | 1.16 (1.03;1.34) 0.07 | 1.38 (1.17;1.66) <0.001 | 3.19 (0.67;22.94) 0.22 | 0.37 (0.07;1.46) 0.95 | 0.91 (0.39;2.13) 1 | 1.01 (0.42;2.41) 1 | 0.74 (0.37;1.44) 1 | |
| IgG3 | 0.01 (0;13.86) 1 | 1.41 (0.65;3.06) 1 | 0.15 (0.06;0.36) <0.001 | 0.84 (0.57;1.22) 1 | 0.74 (0.52;1.03) 0.28 | 1.09 (0.78;1.54) 1 | 1.16 (1.03;1.33) 0.07 | 1.35 (1.15;1.59) <0.001 | 4.39 (1.03;30.19) 0.22 | 0.64 (0.15;2.36) 1 | 0.94 (0.42;2.1) 1 | 1.07 (0.5;2.28) 1 | 0.68 (0.36;1.24) 1 | |
| IgG4 | 0.09 (0;4636.2) 1 | 1.28 (0.6;2.75) 1 | 0.14 (0.05;0.34) <0.001 | 0.83 (0.56;1.2) 1 | 0.72 (0.51;1) 0.28 | 1.12 (0.8;1.58) 1 | 1.16 (1.03;1.33) 0.07 | 1.37 (1.16;1.63) <0.001 | 4.58 (1.06;31.87) 0.22 | 0.55 (0.14;1.96) 1 | 0.92 (0.41;2.04) 1 | 1.01 (0.48;2.13) 1 | 0.69 (0.36;1.29) 1 | |
| IgM | 0.24 (0.1;0.52) <0.001 | 0.87 (0.37;1.98) 1 | 0.22 (0.08;0.57) 0.002 | 0.74 (0.48;1.1) 0.82 | 0.71 (0.48;1.01) 0.28 | 1.02 (0.71;1.46) 1 | 1.24 (1.08;1.44) 0.009 | 1.26 (1.07;1.5) 0.006 | 3.63 (0.79;26) 0.22 | 0.54 (0.13;2.02) 1 | 1.04 (0.44;2.46) 1 | 1.25 (0.56;2.82) 1 | 1.08 (0.54;2.23) 1 | |
| Antibody levels | Sex | Site | WAS | HAZ | Hb | Exposure to malaria | Maternal antibodies | Prior episode † | vaccine | IgG at M0 | IgM at M0 | |||
| OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | OR (CI) P-val | |||
| Children | ||||||||||||||
| IgG | 0.88 (0.5;1.53) 1 | 1.16 (0.49;2.78) 1 | 0.02 (0;0.09) <0.001 | 0.59 (0.38;0.88) 0.043 | 0.79 (0.52;1.18) 1 | 0.71 (0.52;0.96) 0.14 | 1.29 (1.14;1.49) <0.001 | 1.6 (1.21;2.31) 0.001 | 4.78 (1.26;23.32) 0.12 | 0.4 (0.16;1) 0.25 | 0.23 (0.07;0.7) 0.05 | 1.27 (0.41;4.09) 1 | ||
| IgG1 | 0.76 (0.42;1.32) 1 | 1.18 (0.5;2.84) 1 | 0.03 (0.01;0.11) <0.001 | 0.6 (0.38;0.89) 0.043 | 0.79 (0.52;1.17) 1 | 0.73 (0.53;0.97) 0.15 | 1.29 (1.14;1.49) <0.001 | 1.6 (1.22;2.31) 0.001 | 4.89 (1.28;24.2) 0.12 | 0.39 (0.15;0.98) 0.25 | 0.55 (0.24;1.19) 0.5 | 1.25 (0.45;3.62) 1 | ||
| IgG2 | 0.91 (0.52;1.57) 1 | 1.09 (0.44;2.72) 1 | 0.04 (0.01;0.12) <0.001 | 0.59 (0.37;0.9) 0.043 | 0.75 (0.48;1.13) 1 | 0.73 (0.53;0.97) 0.15 | 1.28 (1.13;1.49) <0.001 | 1.54 (1.18;2.22) 0.002 | 4.34 (1.13;21.36) 0.12 | 0.39 (0.15;1) 0.25 | 0.46 (0.18;1.11) 0.42 | 1.31 (0.44;4.03) 1 | ||
| IgG3 | 0.02 (0;0.18) 0.002 | 1.11 (0.44;2.8) 1 | 0.04 (0.01;0.15) <0.001 | 0.56 (0.34;0.88) 0.043 | 0.78 (0.51;1.19) 1 | 0.74 (0.53;1) 0.15 | 1.24 (1.1;1.44) <0.001 | 1.51 (1.13;2.26) 0.007 | 3.41 (0.83;17.99) 0.15 | 0.36 (0.13;0.97) 0.25 | 0.78 (0.42;1.46) 0.61 | 1.44 (0.49;4.49) 1 | ||
| IgG4 | 0.01 (0;0.18) 0.003 | 1.06 (0.42; 2.66) 1 | 0.05 (0.01;0.16) <0.001 | 0.61 (0.38;0.93) 0.043 | 0.81 (0.53;1.22) 1 | 0.72 (0.51;0.97) 0.15 | 1.25 (1.1;1.45) <0.001 | 1.5 (1.11;2.25) 0.007 | 3.65 (0.88;19.45) 0.15 | 0.36 (0.13;0.97) 0.25 | 0.73 (0.4;1.32) 0.61 | 1.25 (0.45;3.64) 1 | ||
| IgM | 0.55 (0.16;1.82) 1 | 1.18 (0.5; 2.84) 1 | 0.04 (0.01;0.13) <0.001 | 0.58 (0.36;0.86) 0.041 | 0.79 (0.52;1.17) 1 | 0.73 (0.53;0.97) 0.15 | 1.29 (1.14;1.49) <0.001 | 1.72 (1.26;2.62) <0.001 | 4.54 (1.19;22.19) 0.12 | 0.4 (0.15;0.99) 0.25 | 0.64 (0.35;1.13) 0.5 | 1.68 (0.51;6.44) 1 | ||
Data from the phase 3 trial participants, including anti-α-Gal antibody data at M3 and covariates. The analysis was performed for all participants together and stratifying by age group (infants and children). Results show those factors that affect the risk of clinical malaria when anti-α-Gal antibodies are taken into account. P-values were adjusted for multiple comparisons through Benjamini-Hochberg and Holm, those significant are in bold.
Age cohort (children vs infants). Sex (male vs female). Site (Manhiça vs Kintampo). WAZ (Weight-for-Age Z-score). HAZ (Height-for-Age Z-score). Hb (Baseline hemoglobin (g/dL). Exposure index (baseline anti-P. falciparum exposure IgM levels). Maternal index (baseline maternally transferred antibodies). †Malaria episode between month 0 and month 3 (yes vs no). ǂMalaria transmission season at month 3 sample collection (low vs high). Vaccine (RTS,S vs comparator).