Results: The prevalence of sub-clinical vitamin A deficiency among primary school children (serum retinol <0.7 µmol / L) was 7.7% (5.7% in urban and 9.7% in rural areas), while almost half of the children (48.9%) with marginal vitamin A deficiency (serum retinol ≥ 0.7 umol / L and <1.05 umol / L).