Assessing the relationship between chronic aflatoxin exposure and hepatitis B virus immune protection in a population of children receiving nutritional support in Rwanda

Chronic aflatoxins exposure may impair immune function, but evidence in African children is limited. We assessed their association with hepatitis B surface antibody (Anti-HBs) levels in Rwandan children receiving nutritional support for malnutrition recovery or prevention. A total of 216 children aged 7–59 months were enrolled, including 70 malnutrition cases and 146 controls. Anti-HBs concentrations were measured using the ARCHITECT System (Abbott Diagnostics), and aflatoxins (AFB1, AFB2, AFG1, AFG2 and AFB1-lysine) were quantified by liquid chromatography-tandem mass spectrometry (LC–MS/MS). Anti-HBs levels were highly variable (median = 84.8 IU/ml, IQR 14.0–283.4). Serum analysis for AFB1-lysine revealed a mean concentration of 23.43 ± 5.76 pg/mg albumin, while none of the samples showed detectable levels of AFB1, AFB2, AFG1, or AFG2 above the limit of detection. In unadjusted analyses, no significant differences in Anti-HBs or aflatoxin levels were observed between cases and controls (Mann–Whitney U, p = 0.452 and p = 0.119, respectively) or between sexs (t-test, p = 0.642 and p = 0.352). Age was not correlated with aflatoxin levels (r = 0.06, p = 0.556). In multivariable linear regression analyses adjusting for age, place of residence, socioeconomic status, and sex, nutritional status emerged as a significant determinant of Anti-HBs levels. Specifically, the control group had higher Anti-HBs levels than the case group (β = 0.573, 95% CI 0.076–1.070, p = 0.024), while aflatoxin exposure showed no independent association with Anti-HBs levels (β = − 0.003, 95% CI − 0.031–0.025, p = 0.832). These findings suggest that, in this population, nutritional status rather than chronic aflatoxins burden, is the primary determinant of Anti-HBs response, highlighting the importance of targeted nutritional interventions to support immune protection in children.