Table 1. Baseline characteristics of the subjects.
| Current malaria | ||||
| Variables | Non-infectedn = 205 | Symptomatic infectionn = 210 | Asymptomatic infectionn = 221 | P valueχ2 |
| n (%) | n (%) | n (%) | ||
| Gender | 0.227 | |||
| Male | 88 (42.93) | 107 (50.95) | 99 (44.80) | |
| Age (years) | <0.0001 | |||
| 5 to 15 | 14 (6.83) | 25 (11.90) | 1 (0.45) | |
| 16 to 30 | 50 (24.39) | 66 (31.43) | 36 (16.29) | |
| 31 to 59 | 98 (47.80) | 83 (39.52) | 145 (65.61) | |
| ≥60 | 21 (10.24) | 21 (10.0) | 20 (9.05) | |
| Years residing in the area | <0.0001 | |||
| ≤2 | 44 (21.46) | 56 (26.67) | 34 (15.38) | |
| 3 to 10 | 20 (9.76) | 41 (19.52) | 19 (8.60) | |
| >10 | 119 (58.05) | 195 (92.86) | 149 (67.42) | |
| Residents per household | <0.0001 | |||
| 1 to 5 | 141 (68.78) | 113 (53.81) | 147 (66.52) | |
| >5 | 42 (20.49) | 82 (39.05) | 55 (24.89) | |
| HBV infection | <0.0001 | |||
| Non-infected | 89 (43.41) | 140 (68.30) | 97 (43.89) | |
| Previous HBV | 65 (31.70) | 51 (24.30) | 77 (34.84) | |
| Current HBV | 29 (14.15) | 04 (1.90) | 28 (12.67) | |
| Vaccinated | 22 (10.73) | 15 (7.14) | 19 (8.60) | |
| Malaria diagnosis ‡ | <0.0001 | |||
| Negative | 205 (100) | - | - | |
| P. vivax | - | 190 (90.48) | 173 (78.28) | |
| P. falciparum | - | 15 (7.14) | 41 (18.55) | |
| P. vivax + P. falciparum | - | 05 (2.38) | 07 (3.17) | |
| Malaria episodes | <0.0001 | |||
| None | 24 (11.71) | 25 (11.90) | 03 (1.36) | |
| 1 to 4 | 07 (3.41) | 58 (27.62) | 03 (1.36) | |
| 5 to 10 | 29 (14.15) | 49 (23.33) | 07 (3.17) | |
| >10 | 123 (60.0) | 63 (30.0) | 189 (85.52) | |
| Plasma IL-10 (pg/mL) § | <0.0001 | |||
| ≤46 | 175 (85.37) | 147 (70.0) | 51 (23.08) | |
| >46 | 08 (3.90) | 48 (22.86) | 151 (68.33) | |
| Plasma IFN-γ (pg/mL) § | <0.0001 | |||
| ≤198 | 154 (75.12) | 116 (55.24) | 148 (66.97) | |
| >198 | 29 (14.15) | 79 (37.62) | 54 (24.43) | |
A Chi-square test was performed to compare the distribution of each variable between the groups.
Individuals presenting AgHBS−/anti-HBS+/anti-HBc+ with no HBV DNA amplification by quantitative RT-PCR (qPCR) were considered to have previous HBV infection, those presenting AgHBS+/anti-HBS− and detectable viremia by qPCR were considered currently infected with HBV and those with AgHBS−/anti-HBS+/anti-HBc− were considered vaccinated against the virus.
‡Malaria diagnosis was based on light microscopy and confirmed by a nested RT-PCR molecular test, as described in methods.
§Cut-off IL-10 and IFN- γ plasma levels were determined by choosing the values that implied the highest likelihood ratio in discriminating asymptomatic from symptomatic malaria infection using a ROC analysis.